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Human brain

2011-09-28T13:23:40Z

PhineasG: /* Evolution */ poorly referenced section (i'll try to replace soon)

{{About|features specific to the human brain|basic information about brains|Brain}}
{{Infobox Anatomy
| Name = Human brain
| Latin = Cerebrum
| GraySubject = 184
| GrayPage = 736
| Image = Skull and brain normal human.svg
| Caption = Human brain and skull
| Image2 = Cerebral lobes.png
| Caption2 = Cerebral lobes: the [[frontal lobe]] (pink), [[parietal lobe]] (green) and [[occipital lobe]] (blue)
| Width = 125px
| Precursor =
| System = [[Central nervous system]]
| Artery = [[Anterior communicating artery]], [[middle cerebral artery]]
| Vein = [[Cerebral veins]], [[external veins]], [[basal vein]], [[terminal vein]], [[choroid vein]], [[cerebellar veins]]
| Nerve =
| Lymph =
| Precursor =
| MeshName =
| MeshNumber =
| Dorlands =
| DorlandsID =
}}
The '''human brain''' is the center of the human [[nervous system]]. Enclosed in the [[human skull|cranium]], the human brain has the same general structure as that of other [[mammal]]s, but is over three times larger than the brain of a typical mammal with an equivalent body size.<ref>[[Donald Johanson|Johanson, D. C.]] (1996). ''From Lucy to language''. New York: Simon and Schuster, [http://books.google.com/books?id=-VKEjAbpggcC&pg=PA80 p. 80].</ref> Most of the spatial expansion comes from the [[cerebral cortex]], a convoluted layer of neural tissue which covers the surface of the [[forebrain]]. Especially expanded are the [[frontal lobes]], which are associated with [[executive functions]] such as self-control, planning, reasoning, and abstract thought. The portion of the brain devoted to vision, the [[occipital lobe]], is also greatly enlarged in human beings.

Brain evolution, from the earliest [[shrew]]-like mammals through [[primate]]s to [[hominid]]s, is marked by a steady increase in [[encephalization]], or the ratio of brain to body size. Estimates vary for the number of neuronal and non-neuronal cells contained in the brain, ranging from 80 or 90 billion (~85 109) non-neuronal cells ([[glial cell]]s) and an approximately equal number of (~86 109) [[neuron]]s,<ref>{{cite journal |last1=Azevedo |first1=Frederico |last2=Carvalho |first2=Ludmila |last3=Grinberg |first3=Lea |last4=Farfel |first4=José |last5=Ferretti |first5=Renata |last6=Leite |first6=Renata |last7=Filho |first7=Wilson |last8=Lent |first8=Roberto |last9=Herculano-Houzel |first9=Suzana |year=2009 |title=Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled-up primate brain |journal=[[The Journal of Comparative Neurology]] |volume=513 |issue=5 |pages=532–541 |doi=10.1002/cne.21974|pmid=19226510}}</ref> of which about 10 billion (1010) are [[pyramidal cell|cortical pyramidal cells]], to over 120 billion neuronal cells, with an approximately equal number of non-neuronal cells.<ref>{{cite journal |url=http://www.frontiersin.org/human_neuroscience/10.3389/neuro.09.031.2009/full |title=The human brain in numbers: a linearly scaled-up primate brain |last=Herculano-Houzel |first=Suzana |date=November 9, 2009 |publisher=Frontiers In Human Neuroscience |doi=10.3389/neuro.09.031.2009 |accessdate=May 11, 2011}}</ref> These cells pass signals to each other via as many as 1000 trillion (1015, 1 quadrillion) [[synapse|synaptic connections]].<ref>{{Cite pmid|8527499}}</ref> Due to evolution, however, the modern human brain has been shrinking over the past 28,000 years.<ref>{{cite news| url=http://www.timesonline.co.uk/tol/news/science/article7060327.ece | location=London | work=The Times | first1=Adam | last1=Sage | title=Cro Magnon skull supports theory that human brains have begun to shrink | date=2010-03-13}}</ref><ref>{{cite web |url=http://discovermagazine.com/2010/sep/25-modern-humans-smart-why-brain-shrinking |title=If Modern Humans Are So Smart, Why Are Our Brains Shrinking? |last1=McAuliffe |first1=Kathleen |date=January 20, 2011 |work=[[Discover (magazine)|Discover]] |accessdate=May 7, 2011}}</ref>

The brain monitors and regulates the body's actions and reactions. It continuously receives sensory information, and rapidly analyzes this data and then responds accordingly by controlling bodily actions and functions. The [[brainstem]] controls breathing, heart rate, and other [[autonomic nervous system|autonomic]] processes that are independent of conscious brain functions. The [[neocortex]] is the center of higher-order thinking, learning, and memory. The [[cerebellum]] is responsible for the body's balance, posture, and the coordination of movement.

Despite being protected by the thick bones of the skull, suspended in [[cerebrospinal fluid]], and isolated from the bloodstream by the [[blood-brain barrier]], the human brain is susceptible to many types of damage and disease. The most common forms of physical damage are [[closed head injuries]] such as a blow to the [[human head|head]], a [[stroke]], or poisoning by a wide variety of chemicals that can act as [[neurotoxin]]s. Infection of the brain, though serious, is rare due to the biological barriers which protect it. The human brain is also susceptible to degenerative disorders, such as [[Parkinson's disease]], [[multiple sclerosis]], and [[Alzheimer's disease]]. A number of psychiatric conditions, such as [[schizophrenia]] and [[major depressive disorder|depression]], are thought to be associated with brain dysfunctions, although the nature of such brain anomalies is not well understood.<ref>{{cite pmid|12052915}}</ref>

==Structure==
{{See|Brain size}}
[[Image:Visible Human head slice.jpg|thumb|200px|right|Bisection of the head of an adult man, showing the cerebral cortex and underlying white matter<ref>From the [[National Library of Medicine]]'s [[Visible Human Project]]. In this project, two human cadavers (from a man and a woman) were frozen and then sliced into thin sections, which were individually photographed and digitized. The slice here is taken from a small distance below the top of the brain, and shows the cerebral cortex (the convoluted cellular layer on the outside) and the underlying white matter, which consists of [[myelinated]] fiber tracts traveling to and from the cerebral cortex.</ref>]]
The adult human brain weighs on average about 3 lb (1.5 kg)<ref name=CarpenterCh1>[[#refCarpenter|''Carpenter's Human Neuroanatomy'']], Ch. 1</ref> with a [[brain size|size]] (volume) of around 1130 cubic centimetres (cm3) in women and 1260 cm3 in men, although there is substantial individual variation.<ref name="Kelly2007">[[#refCosgrove|Cosgrove et al., 2007]]</ref> Men with the same body height and body surface area as women have on average 100g heavier brains,<ref>{{cite journal|title=Sex differences in relative brain size: The mismeasure of woman, too? |author=C. Davison Ankney |journal=Intelligence|volume=16|issue=3-4|pages=329–336|year=1992|doi=10.1016/0160-2896(92)90013-H}}</ref> although these differences do not correlate in any simple way with gray matter neuron counts or with overall measures of cognitive performance.<ref name="pmid10234034">{{cite journal |author=Gur RC, Turetsky BI, Matsui M, Yan M, Bilker W, Hughett P, Gur RE |title=Sex differences in brain gray and white matter in healthy young adults: correlations with cognitive performance |journal=[[The Journal of Neuroscience]] |volume=19 |issue=10 |pages=4065–72 |year=1999 |month=May |pmid=10234034 |doi= |url=http://www.jneurosci.org/cgi/pmidlookup?view=long&pmid=10234034 |issn= |accessdate=2010-05-13}}</ref> [[Neanderthal]]s, an extinct subspecies of modern humans, had larger brains at adulthood than present-day humans.<ref>[http://blogs.nationalgeographic.com/blogs/news/chiefeditor/2008/09/neanderthal.html ''Neanderthal Brain Size at Birth Sheds Light on Human Evolution'']. National Geographic, 2008-09-09. Retrieved 2010-03-05.</ref> The brain is very soft, having a consistency similar to soft [[Gelatin dessert|gelatin]] or soft [[tofu]].<ref>{{cite web|url=http://www.bookofjoe.com/2006/04/a_healthy_brain.html| title=Another Day in the Frontal Lobe| first=Katrina | last=Firlik| publisher=Random House| date=2 May 2006}}</ref> Despite being referred to as "grey matter", the live cortex is pinkish-beige in color and slightly off-white in the interior. At the age of 20, a man has around 176,000 km and a woman about 149,000 km of myelinated axons in their brains.<ref name="Marner">Marner L, Nyengaard JR, Tang Y, Pakkenberg B. (2003). Marked loss of myelinated nerve fibers in the human brain with age. J Comp Neurol. 462(2):144-52. {{PMID|12794739}}</ref>

===General features===
[[Image:NIA human brain drawing.jpg|thumb|200px|left|Drawing of the human brain, showing several important structures]]
The cerebral hemispheres form the largest part of the human brain and are situated above most other brain structures. They are covered with a [[cortex (anatomy)|cortical layer]] with a convoluted topography.<ref>[[#refPrinciples|''Principles of Neural Science'']], p 324</ref> Underneath the [[cerebrum]] lies the [[brainstem]], resembling a stalk on which the cerebrum is attached. At the rear of the brain, beneath the cerebrum and behind the brainstem, is the [[cerebellum]], a structure with a horizontally furrowed surface that makes it look different from any other brain area. The same structures are present in other mammals, although the cerebellum is not so large relative to the rest of the brain. As a rule, the smaller the cerebrum, the less convoluted the cortex. The cortex of a rat or mouse is almost completely smooth. The cortex of a dolphin or whale, on the other hand, is more convoluted than the cortex of a human.

The dominant feature of the human brain is ''corticalization''. The cerebral cortex in humans is so large that it overshadows every other part of the brain. A few subcortical structures show alterations reflecting this trend. The cerebellum, for example, has a medial zone connected mainly to subcortical motor areas, and a lateral zone connected primarily to the cortex. In humans the lateral zone takes up a much larger fraction of the cerebellum than in most other mammalian species. Corticalization is reflected in function as well as structure. In a rat, surgical removal of the entire cerebral cortex leaves an animal that is still capable of walking around and interacting with the environment.<ref>[[#refVanderwolf1978|Vanderwolf et al., 1978]]</ref> In a human, comparable cerebral cortex damage produces a permanent state of [[coma]]. The amount of association cortex, relative to the other two categories, increases dramatically as one goes from simpler mammals, such as the rat and the cat, to more complex ones, such as the chimpanzee and the human.<ref>[[#refGray|Gray ''Psychology'' 2002]]</ref>

The cerebral cortex is essentially a sheet of neural tissue, folded in a way that allows a large surface area to fit within the confines of the skull. Each cerebral hemisphere, in fact, has a total surface area of about 1.3 square feet.<ref>[[#refToro|Toro et al., 2008]]</ref> Anatomists call each cortical fold a [[Sulcus (neuroanatomy)|sulcus]], and the smooth area between folds a [[gyrus]].

===Cortical divisions===
====Four lobes====
[[Image:Gray728.svg|thumb|250px|The four lobes of the cerebral cortex]]
Outwardly, the cerebral cortex is nearly symmetrical, with left and right hemispheres. Anatomists conventionally divide each hemisphere into four "lobes", the:
*[[Frontal lobe]]
*[[Parietal lobe]]
*[[Occipital lobe]]
*[[Temporal lobe]]
[[Image:Schaedel-mensch-seitenansicht.jpg|thumb|The bones of the human skull]]
This categorization does not actually arise from the structure of the cortex itself: the lobes are named after the bones of the skull that overlie them. There is one exception: the border between the frontal and parietal lobes is shifted backward to the [[central sulcus]], a deep fold that marks the line where the primary somatosensory cortex and primary motor cortex come together.

Although the division of the cortex into hemispheres and lobes is very general and perhaps lack the precision of specifying by brain coordinates (e.g. [[Jean Talairach|Talairach space]]) or through the region of specific brain cytoarchitecture (e.g. [[Brodmann area]]s, or deep brain structures), it is nevertheless useful for discussing general brain anatomy or the locating of lesions in a general area of the brain.

There is a fifth lobe to the cerebral cortex known as the insula or [[insular cortex]], which is only visible if the temporal lobe is pulled down during dissection at the [[lateral sulcus]].

====Major folds====
[[Image:Gray726.png|thumb|200px|right|Major gyri and sulci on the lateral surface of the cortex]]
Although there are enough variations in the shape and placement of gyri and sulci (cortical folds) to make every brain unique, most human brains show sufficiently consistent patterns of folding that allow them to be named. Many of the gyri and sulci are named according to the location on the lobes or other major folds on the cortex. These include:
*''Superior, Middle, Inferior frontal gyrus'': in reference to the frontal lobe
*''Precentral and Postcentral sulcus'': in reference to the central sulcus
*''Trans-occipital sulcus'': in reference to the occipital lobe

Deep folding features in the brain, such as the inter-hemispheric and [[lateral fissure]], which divides the left and right brain, and the lateral sulcus, which "splits-off" the temporal lobe, are present in almost all normal subjects.

===Functional divisions===
{{unreferenced section|date=September 2009}}
Researchers who study the functions of the cortex divide it into three functional categories of regions, or areas. One consists of the primary sensory areas, which receive signals from the [[sensory nerve]]s and tracts by way of relay nuclei in the [[thalamus]]. Primary sensory areas include the visual area of the [[occipital lobe]], the auditory area in parts of the [[temporal lobe]] and [[insular cortex]], and the somatosensory area in the [[parietal lobe]]. A second category is the primary motor area, which sends axons down to motor neurons in the brainstem and spinal cord. This area occupies the rear portion of the frontal lobe, directly in front of the somatosensory area. The third category consists of the remaining parts of the cortex, which are called the [[association areas]]. These areas receive input from the sensory areas and lower parts of the brain and are involved in the complex process that we call perception, thought, and decision making.<ref>Principles of Anatomy and Physiology 12th Edition - Tortora,Page 519.</ref>

====Cytoarchitecture====
[[Image:Brodmann-areas.png|thumb|400px|left|Brodmann's classification of areas of the cortex]]
Different parts of the cerebral cortex are involved in different cognitive and behavioral functions. The differences show up in a number of ways: the effects of localized brain damage, regional activity patterns exposed when the brain is examined using functional imaging techniques, connectivity with subcortical areas, and regional differences in the cellular architecture of the cortex. Anatomists describe most of the cortex—the part they call ''isocortex''—as having six layers, but not all layers are apparent in all areas, and even when a layer is present, its thickness and cellular organization may vary. Several anatomists have [[Cytoarchitectonics of the cerebral cortex|constructed maps of cortical areas]] on the basis of variations in the appearance of the layers as seen with a microscope. One of the most widely used schemes came from [[Brodmann area|Brodmann]], who split the cortex into 51 different areas and assigned each a number (anatomists have since subdivided many of the Brodmann areas). For example, Brodmann area 1 is the primary somatosensory cortex, Brodmann area 17 is the primary visual cortex, and Brodmann area 25 is the anterior cingulate cortex.<ref>Principles of Anatomy and Physiology 12th Edition - Tortora,Page 519-fig.(14.15)</ref>

====Topography====
[[Image:Human motor cortex topography.png|thumb|200px|right|Topography of the primary motor cortex, showing which body part is controlled by each zone]]
Many of the brain areas Brodmann defined have their own complex internal structures. In a number of cases, brain areas are organized into "topographic maps", where adjoining bits of the cortex correspond to adjoining parts of the body, or of some more abstract entity. A simple example of this type of correspondence is the primary motor cortex, a strip of tissue running along the anterior edge of the central sulcus, shown in the image to the right. Motor areas innervating each part of the body arise from a distinct zone, with neighboring body parts represented by neighboring zones. Electrical stimulation of the cortex at any point causes a muscle-contraction in the represented body part. This "somatotopic" representation is not evenly distributed, however. The head, for example, is represented by a region about three times as large as the zone for the entire back and trunk. The size of any zone correlates to the precision of motor control and sensory discrimination possible.{{Citation needed|date=September 2009}} The areas for the lips, fingers, and tongue are particularly large, considering the proportional size of their represented body parts.

In visual areas, the maps are [[retinotopy|retinotopic]]—that is, they reflect the topography of the [[retina]], the layer of light-activated neurons lining the back of the eye. In this case too the representation is uneven: the [[fovea]]—the area at the center of the visual field—is greatly overrepresented compared to the periphery. The visual circuitry in the human cerebral cortex contains several dozen distinct retinotopic maps, each devoted to analyzing the visual input stream in a particular way.{{Citation needed|date=September 2009}} The primary visual cortex (Brodmann area 17), which is the main recipient of direct input from the visual part of the thalamus, contains many neurons that are most easily activated by edges with a particular orientation moving across a particular point in the visual field. Visual areas farther downstream extract features such as color, motion, and shape.

In auditory areas, the primary map is [[tonotopy|tonotopic]]. Sounds are parsed according to frequency (i.e., high pitch vs. low pitch) by subcortical auditory areas, and this parsing is reflected by the primary auditory zone of the cortex. As with the visual system, there are a number of tonotopic cortical maps, each devoted to analyzing sound in a particular way.

Within a topographic map there can sometimes be finer levels of spatial structure. In the primary visual cortex, for example, where the main organization is retinotopic and the main responses are to moving edges, cells that respond to different edge-orientations are spatially segregated from one another.{{Citation needed|date=September 2009}}

==Lateralization==
{{Main|Lateralization of brain function}}

[[Image:Gray722.png|thumb|right|Routing of neural signals from the two eyes to the brain]]
Each hemisphere of the brain interacts primarily with one half of the body, but for reasons that are unclear, the connections are crossed: the left side of the brain interacts with the right side of the body, and vice versa.{{Citation needed|date=February 2010}} Motor connections from the brain to the spinal cord, and sensory connections from the spinal cord to the brain, both cross the midline at brainstem levels. Visual input follows a more complex rule: the optic nerves from the two eyes come together at a point called the [[optic chiasm]], and half of the fibers from each nerve split off to join the other. The result is that connections from the left half of the retina, in both eyes, go to the left side of the brain, whereas connections from the right half of the retina go to the right side of the brain. Because each half of the retina receives light coming from the opposite half of the visual field, the functional consequence is that visual input from the left side of the world goes to the right side of the brain, and vice versa. Thus, the right side of the brain receives somatosensory input from the left side of the body, and visual input from the left side of the visual field—an arrangement that presumably is helpful for visuomotor coordination.

[[Image:Corpus callosum.jpg|thumb|350px|left|The corpus callosum, a nerve bundle connecting the two cerebral hemispheres, with the [[lateral ventricles]] directly below]]
The two cerebral hemispheres are connected by a very large nerve bundle called the [[corpus callosum]], which crosses the midline above the level of the thalamus. There are also two much smaller connections, the [[anterior commissure]] and [[Commissure of fornix|hippocampal commissure]], as well as many subcortical connections that cross the midline. The corpus callosum is the main avenue of communication between the two hemispheres, though. It connects each point on the cortex to the mirror-image point in the opposite hemisphere, and also connects to functionally related points in different cortical areas.

In most respects, the left and right sides of the brain are symmetrical in terms of function. For example, the counterpart of the left-hemisphere motor area controlling the right hand is the right-hemisphere area controlling the left hand. There are, however, several very important exceptions, involving language and spatial cognition. In most people, the left hemisphere is "dominant" for language: a stroke that damages a key language area in the left hemisphere can leave the victim unable to speak or understand, whereas equivalent damage to the right hemisphere would cause only minor impairment to language skills.

A substantial part of our current understanding of the interactions between the two hemispheres has come from the study of "[[split-brain]] patients"—people who underwent surgical transection of the corpus callosum in an attempt to reduce the severity of epileptic seizures. These patients do not show unusual behavior that is immediately obvious, but in some cases can behave almost like two different people in the same body, with the right hand taking an action and then the left hand undoing it. Most such patients, when briefly shown a picture on the right side of the point of visual fixation, are able to describe it verbally, but when the picture is shown on the left, are unable to describe it, but may be able to give an indication with the left hand of the nature of the object shown.

It should be noted that the differences between left and right hemispheres are greatly overblown in much of the popular literature on this topic. The existence of differences has been solidly established, but many popular books go far beyond the evidence in attributing features of personality or intelligence to the left or right hemisphere dominance.{{Citation needed|date=September 2009}}

==Development==
{{Main|Neural development in humans}}
{{See|Human brain development timeline}}
During the first 3 weeks of gestation, the human embryo's [[ectoderm]] forms a thickened strip called the [[neural plate]]. The [[neural plate]] then folds and closes to form the [[neural tube]]. This tube flexes as it grows, forming the crescent-shaped cerebral hemispheres at the head, and the cerebellum and pons towards the tail.
{{Image gallery
|title=
|width=180
|height=180
|lines=3
|Gray651.png|1|Brain of human embryo at 4.5 weeks, showing interior of forebrain
|Gray653.png|2|Brain interior at 5 weeks
|Gray654.png|3|Brain viewed at midline at 3 months
}}

==Evolution==
{{see also|Brain size}}
In the course of evolution, the modern human brain has been shrinking over the past 28,000 years. The male brain has decreased from 1,500 [[Cubic_centimetre|cc]] to 1,350 cc while the female brain has shrunk by the same relative proportion.{{Citation needed|date=September 2011}} For comparison, ''[[Homo erectus]]'', a relative of humans, had a brain size of 1,100 cc.

Studies tend to indicate small to moderate [[correlations]] (averaging around 0.3 to 0.4) between [[Brain size|brain volume]] and [[Intelligence quotient|IQ]]. The most consistent associations are observed within the frontal, temporal, and parietal lobes, the hippocampi, and the cerebellum, but these only account for a relatively small amount of variance in IQ, which itself has only a partial relationship to general intelligence and real-world performance.<ref>[[#refLuders|Luders et al., 2008]]</ref><ref>[[#refHoppe|Hoppe & Stojanovic, 2008]]</ref>{{Full}} Demographic studies have indicated that in humans, [[fertility and intelligence]] tend to be negatively correlated—that is to say, the more intelligent, as measured by IQ, exhibit a lower [[total fertility rate]] than the less intelligent. The present rate of decline is predicted to be 1.34 IQ points per decade.<ref>{{cite doi|10.1017/S0021932009003344}}</ref>

== Sources of information ==
[[Neuroscience|Neuroscientists]], along with researchers from allied disciplines, study how the human brain works. Such research has expanded considerably in recent decades. The "[[Decade of the Brain]]", an initiative of the United States Government in the 1990s, is considered to have marked much of this increase in research.<ref>{{Cite journal|url=http://www.sciencemag.org/cgi/content/summary/284/5415/739|first1=Edward G.|last1=Jones|authorlink1=Edward G. Jones|first2=Lorne M.|last2=Mendell|title=Assessing the Decade of the Brain|journal=Science|doi=10.1126/science.284.5415.739|date=April 30, 1999|volume=284|issue=5415|page=739|accessdate=2010-04-05|publisher=[[American Association for the Advancement of Science]]|pmid=10336393}}</ref>

Information about the structure and function of the human brain comes from a variety of experimental methods. Most information about the cellular components of the brain and how they work comes from studies of animal subjects, using techniques described in the [[brain]] article. Some techniques, however, are used mainly in humans, and therefore are described here.

[[Image:CT of brain of Mikael Häggström large.png|thumb|350px|[[Computed tomography]] of human brain, from [[base of the skull]] to top, taken with intravenous contrast medium]]

===EEG===
By placing electrodes on the scalp it is possible to record the summed electrical activity of the cortex, in a technique known as [[electroencephalography]] (EEG).<ref>[[#refFisch|''Fisch and Spehlmann's EEG primer'']]</ref> EEG measures mass changes in population synaptic activity from the cerebral cortex, but can only detect changes over large areas of the brain, with very little sensitivity for sub-cortical activity. EEG recordings can detect events lasting only a few thousandths of a second. EEG recordings have good temporal resolution, but poor spatial resolution.

===MEG===
Apart from measuring the electric field around the skull it is possible to measure the magnetic field directly in a technique known as [[magnetoencephalography]] (MEG).<ref>[[#refPreissl|Preissl, ''Magnetoencephalography'']]</ref> This technique has the same temporal resolution as EEG but much better spatial resolution, although not as good as [[Magnetic Resonance Imaging]] (MRI). The greatest disadvantage of MEG is that, because the magnetic fields generated by neural activity are very weak, the method is only capable of picking up signals from near the surface of the cortex, and even then, only neurons located in the depths of cortical folds (''sulci'') have dendrites oriented in a way that gives rise to detectable magnetic fields outside the skull.

===Structural and functional imaging===
{{Main|Neuroimaging}}
[[Image:FMRI.jpg|thumb|150px|A scan of the brain using fMRI]]
There are several methods for detecting brain activity changes by three-dimensional imaging of local changes in blood flow. The older methods are [[Single photon emission computed tomography|SPECT]] and [[Positron emission tomography|PET]], which depend on injection of radioactive tracers into the bloodstream. The newest method, [[functional magnetic resonance imaging]] (fMRI), has considerably better spatial resolution and involves no radioactivity.<ref>[[#refBuxton|Buxton, ''Introduction to Functional Magnetic Resonance Imaging'']]</ref> Using the most powerful magnets currently available, fMRI can localize brain activity changes to regions as small as one cubic millimeter. The downside is that the temporal resolution is poor: when brain activity increases, the blood flow response is delayed by 1–5 seconds and lasts for at least 10 seconds. Thus, fMRI is a very useful tool for learning which brain regions are involved in a given behavior, but gives little information about the temporal dynamics of their responses. A major advantage for fMRI is that, because it is non-invasive, it can readily be used on human subjects.

===Effects of brain damage===
{{Main|Neuropsychology}}
A key source of information about the function of brain regions is the effects of damage to them.<ref>[[#refAndrews|Andrews, ''Neuropsychology'']]</ref> In humans, strokes have long provided a "natural laboratory" for studying the effects of brain damage. Most strokes result from a blood clot lodging in the brain and blocking the local blood supply, causing damage or destruction of nearby brain tissue: the range of possible blockages is very wide, leading to a great diversity of stroke symptoms. Analysis of strokes is limited by the fact that damage often crosses into multiple regions of the brain, not along clear-cut borders, making it difficult to draw firm conclusions.

==Language==
[[Image:BrocasAreaSmall.png|thumb|right|250px|Location of two brain areas that play a critical role in language, [[Broca's area]] and [[Wernicke's area]]]]
In human beings, it is the left hemisphere that usually contains the specialized language areas. While this holds true for 97% of right-handed people, about 19% of left-handed people have their language areas in the right hemisphere and as many as 68% of them have some language abilities in both the left and the right hemisphere. {{Citation needed|date=April 2010}} The two hemispheres are thought to contribute to the processing and understanding of language: the left hemisphere processes the [[linguistic meaning]] of [[Prosody (linguistics)|prosody]] (or, the rhythm, stress, and intonation of [[connected speech]]), while the right hemisphere processes the emotions conveyed by prosody.<ref>{{cite web|url=http://umainetoday.umaine.edu/issues/v5i1/stroke.html| title=Deleted Words| first=George| last=Manlove| publisher=UMaine Today Magazine| month=February | year=2005| accessdate=2007-02-09}}</ref> Studies of children have shown that if a child has damage to the left hemisphere, the child may develop language in the right hemisphere instead. The younger the child, the better the recovery. So, although the "natural" tendency is for language to develop on the left, human brains are capable of adapting to difficult circumstances, if the damage occurs early enough.

The first language area within the left hemisphere to be discovered is [[Broca's area]], named after [[Paul Broca]], who discovered the area while studying patients with [[aphasia]], a language disorder. Broca's area doesn't just handle getting language out in a motor sense, though. It seems to be more generally involved in the ability to process grammar itself, at least the more complex aspects of grammar. For example, it handles distinguishing a sentence in passive form from a simpler subject-verb-object sentence — the difference between "The boy was hit by the girl" and "The girl hit the boy."{{citation needed|date=September 2011}}

The second language area to be discovered is called [[Wernicke's area]], after [[Carl Wernicke]], a German neurologist who discovered the area while studying patients who had similar symptoms to Broca's area patients but damage to a different part of their brain. [[Wernicke's aphasia]] is the term for the disorder occurring upon damage to a patient's Wernicke's area.

Wernicke's aphasia does not only affect speech comprehension. People with Wernicke's aphasia also have difficulty recalling the names of objects, often responding with words that sound similar, or the names of related things, as if they are having a hard time recalling word associations{{Citation needed|date=September 2009}}.

==Pathology==
[[Image:Frontotemporal degeneration.png|right|thumb|238px|A human brain showing [[frontotemporal lobar degeneration]] causing frontotemporal dementia]]
Clinically, [[death]] is defined as an absence of brain activity as measured by [[EEG]]. Injuries to the brain tend to affect large areas of the organ, sometimes causing major deficits in intelligence, memory, personality, and movement. Head trauma caused, for example, by vehicular or industrial accidents, is a leading cause of death in youth and middle age. In many cases, more damage is caused by resultant [[edema]] than by the impact itself. [[Stroke]], caused by the blockage or rupturing of blood vessels in the brain, is another major cause of death from brain damage.

Other problems in the brain can be more accurately classified as diseases than as injuries. [[Neurodegenerative disease]]s, such as [[Alzheimer's disease]], [[Parkinson's disease]], [[motor neurone disease]], and [[Huntington's disease]] are caused by the gradual death of individual neurons, leading to diminution in movement control, memory, and cognition.

[[Mental disorder]]s, such as [[clinical depression]], [[schizophrenia]], [[bipolar disorder]] and [[post-traumatic stress disorder]] may involve particular patterns of neuropsychological functioning related to various aspects of mental and somatic function. These disorders may be treated by [[psychotherapy]], [[psychiatric medication]] or social intervention and personal [[Recovery model|recovery]] work; the underlying issues and associated prognosis vary significantly between individuals.

Some infectious diseases affecting the brain are caused by [[virus]]es and [[bacteria]]. Infection of the [[meninges]], the membrane that covers the brain, can lead to [[meningitis]]. [[Bovine spongiform encephalopathy]] (also known as "mad cow disease") is deadly in [[cattle]] and humans and is linked to [[prion]]s. [[Kuru (disease)|Kuru]] is a similar prion-borne degenerative brain disease affecting humans. Both are linked to the ingestion of neural tissue, and may explain the tendency in human and some non-human species to avoid [[cannibalism]]. Viral or bacterial causes have been reported in [[multiple sclerosis]] and [[Parkinson's disease]], and are established causes of [[encephalopathy]], and [[encephalomyelitis]].

Many brain disorders are [[congenital disorder|congenital]], occurring during development. [[Tay-Sachs disease]], [[fragile X syndrome]], and [[Down syndrome]] are all linked to [[gene]]tic and [[chromosome|chromosomal]] errors. Many other syndromes, such as the intrinsic [[circadian rhythm]] disorders, are suspected to be congenital as well. Normal [[neural development|development]] of the brain can be altered by genetic factors, [[Recreational drug use|drug use]], [[nutritional deficiencies]], and [[infectious diseases]] during [[pregnancy]].

Certain brain disorders are treated by [[neurosurgeon]]s, while others are treated by [[neurologist]]s and [[psychiatrist]]s.

[[Image:DTI-sagittal-fibers.jpg|right|thumb|Visualization of a '''[[diffusion tensor imaging]]''' (DTI) measurement of a human [[brain]]. Depicted are reconstructed [[axon]] tracts that run through the mid-[[sagittal]] plane. Especially prominent are the U-shaped fibers that connect the two [[cerebral hemisphere|hemispheres]] through the [[corpus callosum]] (the fibers come out of the image plane and consequently bend towards the top) and the fiber tracts that descend toward the [[Spinal cord|spine]] (blue, within the image plane).]]

==Metabolism==
The brain consumes up to twenty percent of the energy used by the human body, more than any other organ.<ref name="power-sciam">{{cite web|last=Swaminathan|first=Nikhil|title=Why Does the Brain Need So Much Power?|url=http://www.scientificamerican.com/article.cfm?id=why-does-the-brain-need-s|work=[[Scientific American]]|publisher=Scientific American, a Division of Nature America, Inc.|accessdate=19 November 2010|date=29 April 2008}}</ref> Brain metabolism normally is completely dependent upon blood [[glucose]] as an energy source, since [[fatty acid]]s do not cross the [[blood-brain barrier]].<ref>[http://www.medbio.info/Horn/IntMet/integration_of_metabolism%20v4.htm MedBio.info > Integration of Metabolism] Professor em. Robert S. Horn, Oslo, Norway. Retrieved on May 1, 2010. [http://www.medbio.info/Horn/PDF%20files/integration_of_metabolism%20v4.pdf]</ref> During times of low glucose (such as [[fasting]]), the brain will primarily use [[ketone bodies]] for fuel with a smaller requirement for glucose. The brain can also utilize lactate during exercise.<ref>{{cite journal |url=http://www.fasebj.org/cgi/content/abstract/22/10/3443 |title=Lactate fuels the human brain during exercise |last1=Quistorff |first1=Bjørn |last2=Secher |first2=Niels |last3=Van Lieshout |first3=Johanne |date=July 24, 2008 |work=[[The FASEB Journal]]|doi=10.1096/fj.08-106104 |accessdate=May 9, 2011}}</ref> The brain does not store any glucose in the form of [[glycogen]], in contrast, for example, to [[skeletal muscle]].

==Additional images==
{{Commons category| Brain}}
<gallery>
File:Brain - Lobes.png
File:BrainLobesLabelled.jpg
File:Embryonicbrain.png
File:Gray720.png
File:Human brain midsagittal cut .JPG
</gallery>

== See also ==
{{Portalbox|Neuroscience|Thinking}}
* [[Cephalic disorders]]
* [[Cephalization]]
* [[Common misconceptions about the brain]]
* [[History of neuroscience]]
* [[Lateralization of brain function]]
* [[List of neuroscience databases]]
* [[List of regions in the human brain]]
* [[Lobes of the brain]]
* [[Neural development in humans]]
* [[Neuroanatomy]]
* [[Neuroanthropology]]
* [[Neuroscience]]
* [[Philosophy of mind]]
* [[10% of brain myth]]

== Notes ==
{{Reflist|30em}}

==References==
{{Refbegin|2}}

*<cite id="refAndrews">{{cite book
| last = Andrews
| first = DG
| title = Neuropsychology
| publisher = Psychology Press
| year = 2001
| url = http://books.google.com/?id=kiCtU8wBTfwC
| isbn = 9781841691039
}}</cite>

*<cite id="refBuxton">{{cite book
| last = Buxton
| first = RB
| title = An Introduction to Functional Magnetic Resonance Imaging: Principles and Techniques
| publisher = Cambridge University Press
| year = 2002
| url = http://books.google.com/?id=FordF5AN9vwC
| isbn = 9780521581134
}}</cite>

* Campbell, Neil A. and Jane B. Reece. (2005). ''Biology''. Benjamin Cummings. ISBN 0-8053-7171-0

*<cite id="refCosgrove">{{cite journal
| last = Cosgrove
| first = KP
| coauthors = Mazure CM, Staley JK
| url = http://linkinghub.elsevier.com/retrieve/pii/S0006322307001989
| title = Evolving knowledge of sex differences in brain structure, function, and chemistry.
| year = 2007
| journal = Biol Psychiat
| volume = 62
| pages = 847–55
| pmid = 17544382
| doi = 10.1016/j.biopsych.2007.03.001
| issue = 8
| pmc = 2711771
}}</cite>

*<cite id="refFisch">{{cite book
| last = Fisch
| first = BJ
| coauthors = Spehlmann R
| year = 1999
| title = Fisch and Spehlmann's EEG Primer: Basic Principles of Digital and Analog EEG.
| publisher = Elsevier Health Sciences
| isbn = 9780444821485
| url = http://books.google.com/?id=YMHsluy4QygC
}}</cite>

*<cite id="refGray">{{cite book
| last = Gray
| first = Peter
| title = Psychology
| publisher = Worth Publishers
| year = 2002
| edition = 4th
| isbn = 0716751623
}}</cite>

*<cite id="refPrinciples">{{cite book
| last = Kandel
| first = ER
| coauthors = Schwartz JH, Jessel TM
| title = Principles of Neural Science
| year = 2000
| publisher = McGraw-Hill Professional
| isbn = 9780838577011
| url =
}}</cite>

* McGilchrist, Ian (2010), ''The Master and His Emissary''. Yale.

*<cite id="refCarpenter">{{cite book
| title = Carpenter's Human Neuroanatomy
| last=Parent
| first=A
| coauthors=Carpenter MB
| publisher = Williams & Wilkins
| year = 1995
| isbn = 9780683067521
| url = http://books.google.com/?id=IJ5pAAAAMAAJ
}}</cite>

*<cite id="refPreissl">{{cite book
| last = Preissl
| first = H
| year = 2005
| title = Magnetoencephalography
| publisher = Academic Press
| isbn = 9780123668691
| url = http://books.google.com/?id=ElTJAAAACAAJ
}}</cite>

* Ramachanandran, V S (2011), ''The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human''. [[W. W. Norton & Company]].

* Simon, Seymour (1999). ''The Brain''. HarperTrophy. ISBN 0-688-17060-9

* Thompson, Richard F. (2000). ''The Brain: An Introduction to Neuroscience''. Worth Publishers. ISBN 0-7167-3226-2

*<cite id="refToro">{{cite journal
| last = Toro
| first = R
| coauthors = Perron M, Pike B, Richer L. Veillette S, Pausova Z, Paus T
| year = 2008
| title = Brain size and folding of the human cerebral cortex.
| volume = 18
| pages = 2352–7
| url = http://cercor.oxfordjournals.org/cgi/content/abstract/18/10/2352
| pmid = 18267953
| doi = 10.1093/cercor/bhm261
| issue = 10
| journal = Cerebral cortex (New York, N.Y. : 1991)
}}</cite>

*<cite id="refVanderwolf1978">{{cite pmid|564358}}</cite>

{{Refend}}

==External links==
* [http://www.med.harvard.edu/AANLIB/home.html The Whole Brain Atlas]
* [http://primate-brain.org High-Resolution Cytoarchitectural Primate Brain Atlases]
* [http://faculty.washington.edu/chudler/facts.html Brain Facts and Figures]
* [http://www.healthline.com/human-body-maps/brain Interactive Human Brain 3D Tool]

{{Organ systems}}
{{Footer Neuropsychology}}
{{nervous system}}
{{Medulla}}
{{Pons}}
{{Mesencephalon}}
{{Cerebellum}}
{{Diencephalon}}
{{Telencephalon}}

{{DEFAULTSORT:Human Brain}}
[[Category:Brain]]

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[[ka:ადამიანის თავის ტვინი]]
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[[pt:Cérebro humano]]
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Human brain

2011-09-16T20:10:21Z

PhineasG:

{{About|features specific to the human brain|basic information about brains|Brain}}
{{Infobox Anatomy
| Name = Human brain
| Latin = Cerebrum
| GraySubject = 184
| GrayPage = 736
| Image = Skull and brain normal human.svg
| Caption = Human brain and skull
| Image2 = Cerebral lobes.png
| Caption2 = Cerebral lobes: the [[frontal lobe]] (pink), [[parietal lobe]] (green) and [[occipital lobe]] (blue)
| Width = 125px
| Precursor =
| System = [[Central nervous system]]
| Artery = [[Anterior communicating artery]], [[middle cerebral artery]]
| Vein = [[Cerebral veins]], [[external veins]], [[basal vein]], [[terminal vein]], [[choroid vein]], [[cerebellar veins]]
| Nerve =
| Lymph =
| Precursor =
| MeshName =
| MeshNumber =
| Dorlands =
| DorlandsID =
}}
The '''human brain''' is the center of the human [[nervous system]]. Enclosed in the [[human skull|cranium]], the human brain has the same general structure as that of other [[mammal]]s, but is over three times larger than the brain of a typical mammal with an equivalent body size.<ref>[[Donald Johanson|Johanson, D. C.]] (1996). ''From Lucy to language''. New York: Simon and Schuster, [http://books.google.com/books?id=-VKEjAbpggcC&pg=PA80 p. 80].</ref> Most of the spatial expansion comes from the [[cerebral cortex]], a convoluted layer of neural tissue which covers the surface of the [[forebrain]]. Especially expanded are the [[frontal lobes]], which are associated with [[executive functions]] such as self-control, planning, reasoning, and abstract thought. The portion of the brain devoted to vision, the [[occipital lobe]], is also greatly enlarged in human beings.

Brain evolution, from the earliest [[shrew]]-like mammals through [[primate]]s to [[hominid]]s, is marked by a steady increase in [[encephalization]], or the ratio of brain to body size. Estimates vary for the number of neuronal and non-neuronal cells contained in the brain, ranging from 80 or 90 billion (~85 109) non-neuronal cells ([[glial cell]]s) and an approximately equal number of (~86 109) [[neuron]]s,<ref>{{cite journal |last1=Azevedo |first1=Frederico |last2=Carvalho |first2=Ludmila |last3=Grinberg |first3=Lea |last4=Farfel |first4=José |last5=Ferretti |first5=Renata |last6=Leite |first6=Renata |last7=Filho |first7=Wilson |last8=Lent |first8=Roberto |last9=Herculano-Houzel |first9=Suzana |year=2009 |title=Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled-up primate brain |journal=[[The Journal of Comparative Neurology]] |volume=513 |issue=5 |pages=532–541 |doi=10.1002/cne.21974|pmid=19226510}}</ref> of which about 10 billion (1010) are [[pyramidal cell|cortical pyramidal cells]], to over 120 billion neuronal cells, with an approximately equal number of non-neuronal cells.<ref>{{cite journal |url=http://www.frontiersin.org/human_neuroscience/10.3389/neuro.09.031.2009/full |title=The human brain in numbers: a linearly scaled-up primate brain |last=Herculano-Houzel |first=Suzana |date=November 9, 2009 |publisher=Frontiers In Human Neuroscience |doi=10.3389/neuro.09.031.2009 |accessdate=May 11, 2011}}</ref> These cells pass signals to each other via as many as 1000 trillion (1015, 1 quadrillion) [[synapse|synaptic connections]].<ref>{{Cite pmid|8527499}}</ref> Due to evolution, however, the modern human brain has been shrinking over the past 28,000 years.<ref>{{cite news| url=http://www.timesonline.co.uk/tol/news/science/article7060327.ece | location=London | work=The Times | first1=Adam | last1=Sage | title=Cro Magnon skull supports theory that human brains have begun to shrink | date=2010-03-13}}</ref><ref>{{cite web |url=http://discovermagazine.com/2010/sep/25-modern-humans-smart-why-brain-shrinking |title=If Modern Humans Are So Smart, Why Are Our Brains Shrinking? |last1=McAuliffe |first1=Kathleen |date=January 20, 2011 |work=[[Discover (magazine)|Discover]] |accessdate=May 7, 2011}}</ref>

The brain monitors and regulates the body's actions and reactions. It continuously receives sensory information, and rapidly analyzes this data and then responds accordingly by controlling bodily actions and functions. The [[brainstem]] controls breathing, heart rate, and other [[autonomic nervous system|autonomic]] processes that are independent of conscious brain functions. The [[cortex]] is the center of higher-order thinking, learning, and memory. The [[cerebellum]] is responsible for the body's balance, posture, and the coordination of movement.

Despite being protected by the thick bones of the skull, suspended in [[cerebrospinal fluid]], and isolated from the bloodstream by the [[blood-brain barrier]], the human brain is susceptible to many types of damage and disease. The most common forms of physical damage are [[closed head injuries]] such as a blow to the head, a [[stroke]], or poisoning by a wide variety of chemicals that can act as [[neurotoxin]]s. Infection of the brain, though serious, is rare due to the biological barriers which protect it. The human brain is also susceptible to degenerative disorders, such as [[Parkinson's disease]], [[multiple sclerosis]], and [[Alzheimer's disease]]. A number of psychiatric conditions, such as [[autism]], [[schizophrenia]], and [[major depressive disorder|depression]], are thought to be associated with dysfunctions of brain development, although the nature of such brain anomalies is not well understood.<ref>{{cite pmid|12052915}}</ref>

==Structure==
{{See|Brain size}}
[[Image:Visible Human head slice.jpg|thumb|200px|right|Bisection of the head of an adult man, showing the cerebral cortex and underlying white matter<ref>From the [[National Library of Medicine]]'s [[Visible Human Project]]. In this project, two human cadavers (from a man and a woman) were frozen and then sliced into thin sections, which were individually photographed and digitized. The slice here is taken from a small distance below the top of the brain, and shows the cerebral cortex (the convoluted cellular layer on the outside) and the underlying white matter, which consists of [[myelinated]] fiber tracts traveling to and from the cerebral cortex.</ref>]]
The adult human brain weighs on average about 3 lb (1.5 kg)<ref name=CarpenterCh1>[[#refCarpenter|''Carpenter's Human Neuroanatomy'']], Ch. 1</ref> with a [[brain size|size]] (volume) of around 1130 cubic centimetres (cm3) in women and 1260 cm3 in men, although there is substantial individual variation.<ref name="Kelly2007">[[#refCosgrove|Cosgrove et al., 2007]]</ref> Men with the same body height and body surface area as women have on average 100g heavier brains,<ref>{{cite journal|title=Sex differences in relative brain size: The mismeasure of woman, too? |author=C. Davison Ankney |journal=Intelligence|volume=16|issue=3-4|pages=329–336|year=1992|doi=10.1016/0160-2896(92)90013-H}}</ref> although these differences do not correlate in any simple way with gray matter neuron counts or with overall measures of cognitive performance.<ref name="pmid10234034">{{cite journal |author=Gur RC, Turetsky BI, Matsui M, Yan M, Bilker W, Hughett P, Gur RE |title=Sex differences in brain gray and white matter in healthy young adults: correlations with cognitive performance |journal=[[The Journal of Neuroscience]] |volume=19 |issue=10 |pages=4065–72 |year=1999 |month=May |pmid=10234034 |doi= |url=http://www.jneurosci.org/cgi/pmidlookup?view=long&pmid=10234034 |issn= |accessdate=2010-05-13}}</ref> [[Neanderthal]]s, an extinct subspecies of modern humans, had larger brains at adulthood than present-day humans.<ref>[http://blogs.nationalgeographic.com/blogs/news/chiefeditor/2008/09/neanderthal.html ''Neanderthal Brain Size at Birth Sheds Light on Human Evolution'']. National Geographic, 2008-09-09. Retrieved 2010-03-05.</ref> The brain is very soft, having a consistency similar to soft [[Gelatin dessert|gelatin]] or soft [[tofu]].<ref>{{cite web|url=http://www.bookofjoe.com/2006/04/a_healthy_brain.html| title=Another Day in the Frontal Lobe| first=Katrina | last=Firlik| publisher=Random House| date=2 May 2006}}</ref> Despite being referred to as "grey matter", the live cortex is pinkish-beige in color and slightly off-white in the interior. At the age of 20, a man has around 176,000 km and a woman about 149,000 km of myelinated axons in their brains.<ref name="Marner">Marner L, Nyengaard JR, Tang Y, Pakkenberg B. (2003). Marked loss of myelinated nerve fibers in the human brain with age. J Comp Neurol. 462(2):144-52. {{PMID|12794739}}</ref>

===General features===
[[Image:NIA human brain drawing.jpg|thumb|200px|left|Drawing of the human brain, showing several important structures]]
The cerebral hemispheres form the largest part of the human brain and are situated above most other brain structures. They are covered with a [[cortex (anatomy)|cortical layer]] with a convoluted topography.<ref>[[#refPrinciples|''Principles of Neural Science'']], p 324</ref> Underneath the [[cerebrum]] lies the [[brainstem]], resembling a stalk on which the cerebrum is attached. At the rear of the brain, beneath the cerebrum and behind the brainstem, is the [[cerebellum]], a structure with a horizontally furrowed surface that makes it look different from any other brain area. The same structures are present in other mammals, although the cerebellum is not so large relative to the rest of the brain. As a rule, the smaller the cerebrum, the less convoluted the cortex. The cortex of a rat or mouse is almost completely smooth. The cortex of a dolphin or whale, on the other hand, is more convoluted than the cortex of a human.

The dominant feature of the human brain is ''corticalization''. The cerebral cortex in humans is so large that it overshadows every other part of the brain. A few subcortical structures show alterations reflecting this trend. The cerebellum, for example, has a medial zone connected mainly to subcortical motor areas, and a lateral zone connected primarily to the cortex. In humans the lateral zone takes up a much larger fraction of the cerebellum than in most other mammalian species. Corticalization is reflected in function as well as structure. In a rat, surgical removal of the entire cerebral cortex leaves an animal that is still capable of walking around and interacting with the environment.<ref>[[#refVanderwolf1978|Vanderwolf et al., 1978]]</ref> In a human, comparable cerebral cortex damage produces a permanent state of [[coma]]. The amount of association cortex, relative to the other two categories, increases dramatically as one goes from simpler mammals, such as the rat and the cat, to more complex ones, such as the chimpanzee and the human.<ref>[[#refGray|Gray ''Psychology'' 2002]]</ref>

The cerebral cortex is essentially a sheet of neural tissue, folded in a way that allows a large surface area to fit within the confines of the skull. Each cerebral hemisphere, in fact, has a total surface area of about 1.3 square feet.<ref>[[#refToro|Toro et al., 2008]]</ref> Anatomists call each cortical fold a [[Sulcus (neuroanatomy)|sulcus]], and the smooth area between folds a [[gyrus]].

===Cortical divisions===
====Four lobes====
[[Image:Gray728.svg|thumb|250px|The four lobes of the cerebral cortex]]
Outwardly, the cerebral cortex is nearly symmetrical, with left and right hemispheres. Anatomists conventionally divide each hemisphere into four "lobes", the:
*[[Frontal lobe]]
*[[Parietal lobe]]
*[[Occipital lobe]]
*[[Temporal lobe]]
[[Image:Schaedel-mensch-seitenansicht.jpg|thumb|The bones of the human skull]]
This categorization does not actually arise from the structure of the cortex itself: the lobes are named after the bones of the skull that overlie them. There is one exception: the border between the frontal and parietal lobes is shifted backward to the [[central sulcus]], a deep fold that marks the line where the primary somatosensory cortex and primary motor cortex come together.

Although the division of the cortex into hemispheres and lobes is very general and perhaps lack the precision of specifying by brain coordinates (e.g. [[Jean Talairach|Talairach space]]) or through the region of specific brain cytoarchitecture (e.g. [[Brodmann area]]s, or deep brain structures), it is nevertheless useful for discussing general brain anatomy or the locating of lesions in a general area of the brain.

There is a fifth lobe to the cerebral cortex known as the insula or [[insular cortex]], which is only visible if the temporal lobe is pulled down during dissection at the [[lateral sulcus]].

====Major folds====
[[Image:Gray726.png|thumb|200px|right|Major gyri and sulci on the lateral surface of the cortex]]
Although there are enough variations in the shape and placement of gyri and sulci (cortical folds) to make every brain unique, most human brains show sufficiently consistent patterns of folding that allow them to be named. Many of the gyri and sulci are named according to the location on the lobes or other major folds on the cortex. These include:
*''Superior, Middle, Inferior frontal gyrus'': in reference to the frontal lobe
*''Precentral and Postcentral sulcus'': in reference to the central sulcus
*''Trans-occipital sulcus'': in reference to the occipital lobe

Deep folding features in the brain, such as the inter-hemispheric and [[lateral fissure]], which divides the left and right brain, and the lateral sulcus, which "splits-off" the temporal lobe, are present in almost all normal subjects.

===Functional divisions===
{{unreferenced section|date=September 2009}}
Researchers who study the functions of the cortex divide it into three functional categories of regions, or areas. One consists of the primary sensory areas, which receive signals from the [[sensory nerve]]s and tracts by way of relay nuclei in the [[thalamus]]. Primary sensory areas include the visual area of the [[occipital lobe]], the auditory area in parts of the [[temporal lobe]] and [[insular cortex]], and the somatosensory area in the [[parietal lobe]]. A second category is the primary motor area, which sends axons down to motor neurons in the brainstem and spinal cord. This area occupies the rear portion of the frontal lobe, directly in front of the somatosensory area. The third category consists of the remaining parts of the cortex, which are called the [[association areas]]. These areas receive input from the sensory areas and lower parts of the brain and are involved in the complex process that we call perception, thought, and decision making.<ref>Principles of Anatomy and Physiology 12th Edition - Tortora,Page 519.</ref>

====Cytoarchitecture====
[[Image:Brodmann-areas.png|thumb|400px|left|Brodmann's classification of areas of the cortex]]
Different parts of the cerebral cortex are involved in different cognitive and behavioral functions. The differences show up in a number of ways: the effects of localized brain damage, regional activity patterns exposed when the brain is examined using functional imaging techniques, connectivity with subcortical areas, and regional differences in the cellular architecture of the cortex. Anatomists describe most of the cortex—the part they call ''isocortex''—as having six layers, but not all layers are apparent in all areas, and even when a layer is present, its thickness and cellular organization may vary. Several anatomists have [[Cytoarchitectonics of the cerebral cortex|constructed maps of cortical areas]] on the basis of variations in the appearance of the layers as seen with a microscope. One of the most widely used schemes came from [[Brodmann area|Brodmann]], who split the cortex into 51 different areas and assigned each a number (anatomists have since subdivided many of the Brodmann areas). For example, Brodmann area 1 is the primary somatosensory cortex, Brodmann area 17 is the primary visual cortex, and Brodmann area 25 is the anterior cingulate cortex.<ref>Principles of Anatomy and Physiology 12th Edition - Tortora,Page 519-fig.(14.15)</ref>

====Topography====
[[Image:Human motor cortex topography.png|thumb|200px|right|Topography of the primary motor cortex, showing which body part is controlled by each zone]]
Many of the brain areas Brodmann defined have their own complex internal structures. In a number of cases, brain areas are organized into "topographic maps", where adjoining bits of the cortex correspond to adjoining parts of the body, or of some more abstract entity. A simple example of this type of correspondence is the primary motor cortex, a strip of tissue running along the anterior edge of the central sulcus, shown in the image to the right. Motor areas innervating each part of the body arise from a distinct zone, with neighboring body parts represented by neighboring zones. Electrical stimulation of the cortex at any point causes a muscle-contraction in the represented body part. This "somatotopic" representation is not evenly distributed, however. The head, for example, is represented by a region about three times as large as the zone for the entire back and trunk. The size of any zone correlates to the precision of motor control and sensory discrimination possible.{{Citation needed|date=September 2009}} The areas for the lips, fingers, and tongue are particularly large, considering the proportional size of their represented body parts.

In visual areas, the maps are [[retinotopy|retinotopic]]—that is, they reflect the topography of the [[retina]], the layer of light-activated neurons lining the back of the eye. In this case too the representation is uneven: the [[fovea]]—the area at the center of the visual field—is greatly overrepresented compared to the periphery. The visual circuitry in the human cerebral cortex contains several dozen distinct retinotopic maps, each devoted to analyzing the visual input stream in a particular way.{{Citation needed|date=September 2009}} The primary visual cortex (Brodmann area 17), which is the main recipient of direct input from the visual part of the thalamus, contains many neurons that are most easily activated by edges with a particular orientation moving across a particular point in the visual field. Visual areas farther downstream extract features such as color, motion, and shape.

In auditory areas, the primary map is [[tonotopy|tonotopic]]. Sounds are parsed according to frequency (i.e., high pitch vs. low pitch) by subcortical auditory areas, and this parsing is reflected by the primary auditory zone of the cortex. As with the visual system, there are a number of tonotopic cortical maps, each devoted to analyzing sound in a particular way.

Within a topographic map there can sometimes be finer levels of spatial structure. In the primary visual cortex, for example, where the main organization is retinotopic and the main responses are to moving edges, cells that respond to different edge-orientations are spatially segregated from one another.{{Citation needed|date=September 2009}}

==Lateralization==
{{Main|Lateralization of brain function}}

[[Image:Gray722.png|thumb|right|Routing of neural signals from the two eyes to the brain]]
Each hemisphere of the brain interacts primarily with one half of the body, but for reasons that are unclear, the connections are crossed: the left side of the brain interacts with the right side of the body, and vice versa.{{Citation needed|date=February 2010}} Motor connections from the brain to the spinal cord, and sensory connections from the spinal cord to the brain, both cross the midline at brainstem levels. Visual input follows a more complex rule: the optic nerves from the two eyes come together at a point called the [[optic chiasm]], and half of the fibers from each nerve split off to join the other. The result is that connections from the left half of the retina, in both eyes, go to the left side of the brain, whereas connections from the right half of the retina go to the right side of the brain. Because each half of the retina receives light coming from the opposite half of the visual field, the functional consequence is that visual input from the left side of the world goes to the right side of the brain, and vice versa. Thus, the right side of the brain receives somatosensory input from the left side of the body, and visual input from the left side of the visual field—an arrangement that presumably is helpful for visuomotor coordination.

[[Image:Corpus callosum.jpg|thumb|350px|left|The corpus callosum, a nerve bundle connecting the two cerebral hemispheres, with the [[lateral ventricles]] directly below]]
The two cerebral hemispheres are connected by a very large nerve bundle called the [[corpus callosum]], which crosses the midline above the level of the thalamus. There are also two much smaller connections, the [[anterior commissure]] and [[Commissure of fornix|hippocampal commissure]], as well as many subcortical connections that cross the midline. The corpus callosum is the main avenue of communication between the two hemispheres, though. It connects each point on the cortex to the mirror-image point in the opposite hemisphere, and also connects to functionally related points in different cortical areas.

In most respects, the left and right sides of the brain are symmetrical in terms of function. For example, the counterpart of the left-hemisphere motor area controlling the right hand is the right-hemisphere area controlling the left hand. There are, however, several very important exceptions, involving language and spatial cognition. In most people, the left hemisphere is "dominant" for language: a stroke that damages a key language area in the left hemisphere can leave the victim unable to speak or understand, whereas equivalent damage to the right hemisphere would cause only minor impairment to language skills.

A substantial part of our current understanding of the interactions between the two hemispheres has come from the study of "[[split-brain]] patients"—people who underwent surgical transection of the corpus callosum in an attempt to reduce the severity of epileptic seizures. These patients do not show unusual behavior that is immediately obvious, but in some cases can behave almost like two different people in the same body, with the right hand taking an action and then the left hand undoing it. Most such patients, when briefly shown a picture on the right side of the point of visual fixation, are able to describe it verbally, but when the picture is shown on the left, are unable to describe it, but may be able to give an indication with the left hand of the nature of the object shown.

It should be noted that the differences between left and right hemispheres are greatly overblown in much of the popular literature on this topic. The existence of differences has been solidly established, but many popular books go far beyond the evidence in attributing features of personality or intelligence to the left or right hemisphere dominance.{{Citation needed|date=September 2009}}

==Development==
{{Main|Neural development in humans}}
{{See|Human brain development timeline}}
During the first 3 weeks of gestation, the human embryo's [[ectoderm]] forms a thickened strip called the [[neural plate]]. The [[neural plate]] then folds and closes to form the [[neural tube]]. This tube flexes as it grows, forming the crescent-shaped cerebral hemispheres at the head, and the cerebellum and pons towards the tail.
{{Image gallery
|title=
|width=180
|height=180
|lines=3
|Gray651.png|1|Brain of human embryo at 4.5 weeks, showing interior of forebrain
|Gray653.png|2|Brain interior at 5 weeks
|Gray654.png|3|Brain viewed at midline at 3 months
}}

==Evolution==
{{see also|Brain size}}
In the course of evolution, the modern human brain has been shrinking over the past 28,000 years. The male brain has decreased from 1,500 [[cc]] to 1,350 cc while the female brain has shrunk by the same relative proportion. For comparison, ''[[Homo erectus]]'', a relative of humans, had a brain size of 1,100 cc.

Studies tend to indicate small to moderate [[correlations]] (averaging around 0.3 to 0.4) between [[Brain size|brain volume]] and [[Intelligence quotient|IQ]]. The most consistent associations are observed within the frontal, temporal, and parietal lobes, the hippocampi, and the cerebellum, but these only account for a relatively small amount of variance in IQ, which itself has only a partial relationship to general intelligence and real-world performance.<ref>[[#refLuders|Luders et al., 2008]]</ref><ref>[[#refHoppe|Hoppe & Stojanovic, 2008]]</ref> Demographic studies have indicated that in humans, [[fertility and intelligence]] tend to be negatively correlated—that is to say, the more intelligent, as measured by IQ, exhibit a lower [[total fertility rate]] than the less intelligent. The present rate of decline is predicted to be 1.34 IQ points per decade.<ref>{{cite doi|10.1017/S0021932009003344}}</ref>

== Sources of information ==
[[Neuroscience|Neuroscientists]], along with researchers from allied disciplines, study how the human brain works. Such research has expanded considerably in recent decades. The "[[Decade of the Brain]]", an initiative of the United States Government in the 1990s, is considered to have marked much of this increase in research.<ref>{{Cite journal|url=http://www.sciencemag.org/cgi/content/summary/284/5415/739|first1=Edward G.|last1=Jones|authorlink1=Edward G. Jones|first2=Lorne M.|last2=Mendell|title=Assessing the Decade of the Brain|journal=Science|doi=10.1126/science.284.5415.739|date=April 30, 1999|volume=284|issue=5415|page=739|accessdate=2010-04-05|publisher=[[American Association for the Advancement of Science]]|pmid=10336393}}</ref>

Information about the structure and function of the human brain comes from a variety of experimental methods. Most information about the cellular components of the brain and how they work comes from studies of animal subjects, using techniques described in the [[brain]] article. Some techniques, however, are used mainly in humans, and therefore are described here.

[[Image:CT of brain of Mikael Häggström large.png|thumb|350px|[[Computed tomography]] of human brain, from [[base of the skull]] to top, taken with intravenous contrast medium]]

===EEG===
By placing electrodes on the scalp it is possible to record the summed electrical activity of the cortex, in a technique known as [[electroencephalography]] (EEG).<ref>[[#refFisch|''Fisch and Spehlmann's EEG primer'']]</ref> EEG measures mass changes in population synaptic activity from the cerebral cortex, but can only detect changes over large areas of the brain, with very little sensitivity for sub-cortical activity. EEG recordings can detect events lasting only a few thousandths of a second. EEG recordings have good temporal resolution, but poor spatial resolution.

===MEG===
Apart from measuring the electric field around the skull it is possible to measure the magnetic field directly in a technique known as [[magnetoencephalography]] (MEG).<ref>[[#refPreissl|Preissl, ''Magnetoencephalography'']]</ref> This technique has the same temporal resolution as EEG but much better spatial resolution, although not as good as [[Magnetic Resonance Imaging]] (MRI). The greatest disadvantage of MEG is that, because the magnetic fields generated by neural activity are very weak, the method is only capable of picking up signals from near the surface of the cortex, and even then, only neurons located in the depths of cortical folds (''sulci'') have dendrites oriented in a way that gives rise to detectable magnetic fields outside the skull.

===Structural and functional imaging===
{{Main|Neuroimaging}}
[[Image:FMRI.jpg|thumb|150px|A scan of the brain using fMRI]]
There are several methods for detecting brain activity changes by three-dimensional imaging of local changes in blood flow. The older methods are [[Single photon emission computed tomography|SPECT]] and [[Positron emission tomography|PET]], which depend on injection of radioactive tracers into the bloodstream. The newest method, [[functional magnetic resonance imaging]] (fMRI), has considerably better spatial resolution and involves no radioactivity.<ref>[[#refBuxton|Buxton, ''Introduction to Functional Magnetic Resonance Imaging'']]</ref> Using the most powerful magnets currently available, fMRI can localize brain activity changes to regions as small as one cubic millimeter. The downside is that the temporal resolution is poor: when brain activity increases, the blood flow response is delayed by 1–5 seconds and lasts for at least 10 seconds. Thus, fMRI is a very useful tool for learning which brain regions are involved in a given behavior, but gives little information about the temporal dynamics of their responses. A major advantage for fMRI is that, because it is non-invasive, it can readily be used on human subjects.

===Effects of brain damage===
{{Main|Neuropsychology}}
A key source of information about the function of brain regions is the effects of damage to them.<ref>[[#refAndrews|Andrews, ''Neuropsychology'']]</ref> In humans, strokes have long provided a "natural laboratory" for studying the effects of brain damage. Most strokes result from a blood clot lodging in the brain and blocking the local blood supply, causing damage or destruction of nearby brain tissue: the range of possible blockages is very wide, leading to a great diversity of stroke symptoms. Analysis of strokes is limited by the fact that damage often crosses into multiple regions of the brain, not along clear-cut borders, making it difficult to draw firm conclusions.

==Language==
[[Image:BrocasAreaSmall.png|thumb|right|250px|Location of two brain areas that play a critical role in language, [[Broca's area]] and [[Wernicke's area]]]]
In human beings, it is the left hemisphere that usually contains the specialized language areas. While this holds true for 97% of right-handed people, about 19% of left-handed people have their language areas in the right hemisphere and as many as 68% of them have some language abilities in both the left and the right hemisphere. {{Citation needed|date=April 2010}} The two hemispheres are thought to contribute to the processing and understanding of language: the left hemisphere processes the [[linguistic meaning]] of [[Prosody (linguistics)|prosody]] (or, the rhythm, stress, and intonation of [[connected speech]]), while the right hemisphere processes the emotions conveyed by prosody.<ref>{{cite web|url=http://umainetoday.umaine.edu/issues/v5i1/stroke.html| title=Deleted Words| first=George| last=Manlove| publisher=UMaine Today Magazine| month=February | year=2005| accessdate=2007-02-09}}</ref> Studies of children have shown that if a child has damage to the left hemisphere, the child may develop language in the right hemisphere instead. The younger the child, the better the recovery. So, although the "natural" tendency is for language to develop on the left, human brains are capable of adapting to difficult circumstances, if the damage occurs early enough.

The first language area within the left hemisphere to be discovered is [[Broca's area]], named after [[Paul Broca]], who discovered the area while studying patients with [[aphasia]], a language disorder. Broca's area doesn't just handle getting language out in a motor sense, though. It seems to be more generally involved in the ability to process grammar itself, at least the more complex aspects of grammar. For example, it handles distinguishing a sentence in passive form from a simpler subject-verb-object sentence — the difference between "The boy was hit by the girl" and "The girl hit the boy."{{citation needed|date=September 2011}}

The second language area to be discovered is called [[Wernicke's area]], after [[Carl Wernicke]], a German neurologist who discovered the area while studying patients who had similar symptoms to Broca's area patients but damage to a different part of their brain. [[Wernicke's aphasia]] is the term for the disorder occurring upon damage to a patient's Wernicke's area.

Wernicke's aphasia does not only affect speech comprehension. People with Wernicke's aphasia also have difficulty recalling the names of objects, often responding with words that sound similar, or the names of related things, as if they are having a hard time recalling word associations{{Citation needed|date=September 2009}}.

==Pathology==
[[Image:Frontotemporal degeneration.png|right|thumb|238px|A human brain showing [[frontotemporal lobar degeneration]] causing frontotemporal dementia]]
Clinically, [[death]] is defined as an absence of brain activity as measured by [[EEG]]. Injuries to the brain tend to affect large areas of the organ, sometimes causing major deficits in intelligence, memory, personality, and movement. Head trauma caused, for example, by vehicular or industrial accidents, is a leading cause of death in youth and middle age. In many cases, more damage is caused by resultant [[edema]] than by the impact itself. [[Stroke]], caused by the blockage or rupturing of blood vessels in the brain, is another major cause of death from brain damage.

Other problems in the brain can be more accurately classified as diseases than as injuries. [[Neurodegenerative disease]]s, such as [[Alzheimer's disease]], [[Parkinson's disease]], [[motor neurone disease]], and [[Huntington's disease]] are caused by the gradual death of individual neurons, leading to diminution in movement control, memory, and cognition.

[[Mental disorder]]s, such as [[clinical depression]], [[schizophrenia]], [[bipolar disorder]] and [[post-traumatic stress disorder]] may involve particular patterns of neuropsychological functioning related to various aspects of mental and somatic function. These disorders may be treated by [[psychotherapy]], [[psychiatric medication]] or social intervention and personal [[Recovery model|recovery]] work; the underlying issues and associated prognosis vary significantly between individuals.

Some infectious diseases affecting the brain are caused by [[virus]]es and [[bacteria]]. Infection of the [[meninges]], the membrane that covers the brain, can lead to [[meningitis]]. [[Bovine spongiform encephalopathy]] (also known as "mad cow disease") is deadly in [[cattle]] and humans and is linked to [[prion]]s. [[Kuru (disease)|Kuru]] is a similar prion-borne degenerative brain disease affecting humans. Both are linked to the ingestion of neural tissue, and may explain the tendency in human and some non-human species to avoid [[cannibalism]]. Viral or bacterial causes have been reported in [[multiple sclerosis]] and [[Parkinson's disease]], and are established causes of [[encephalopathy]], and [[encephalomyelitis]].

Many brain disorders are [[congenital disorder|congenital]], occurring during development. [[Tay-Sachs disease]], [[fragile X syndrome]], and [[Down syndrome]] are all linked to [[gene]]tic and [[chromosome|chromosomal]] errors. Many other syndromes, such as the intrinsic [[circadian rhythm]] disorders, are suspected to be congenital as well. Normal [[neural development|development]] of the brain can be altered by genetic factors, [[Recreational drug use|drug use]], [[nutritional deficiencies]], and [[infectious diseases]] during [[pregnancy]].

Certain brain disorders are treated by [[neurosurgeon]]s, while others are treated by [[neurologist]]s and [[psychiatrist]]s.

[[Image:DTI-sagittal-fibers.jpg|right|thumb|Visualization of a '''[[diffusion tensor imaging]]''' (DTI) measurement of a human [[brain]]. Depicted are reconstructed [[axon]] tracts that run through the mid-[[sagittal]] plane. Especially prominent are the U-shaped fibers that connect the two [[cerebral hemisphere|hemispheres]] through the [[corpus callosum]] (the fibers come out of the image plane and consequently bend towards the top) and the fiber tracts that descend toward the [[Spinal cord|spine]] (blue, within the image plane).]]

==Metabolism==
The brain consumes up to twenty percent of the energy used by the human body, more than any other organ.<ref name="power-sciam">{{cite web|last=Swaminathan|first=Nikhil|title=Why Does the Brain Need So Much Power?|url=http://www.scientificamerican.com/article.cfm?id=why-does-the-brain-need-s|work=[[Scientific American]]|publisher=Scientific American, a Division of Nature America, Inc.|accessdate=19 November 2010|date=29 April 2008}}</ref> Brain metabolism normally is completely dependent upon blood [[glucose]] as an energy source, since [[fatty acid]]s do not cross the [[blood-brain barrier]].<ref>[http://www.medbio.info/Horn/IntMet/integration_of_metabolism%20v4.htm MedBio.info > Integration of Metabolism] Professor em. Robert S. Horn, Oslo, Norway. Retrieved on May 1, 2010. [http://www.medbio.info/Horn/PDF%20files/integration_of_metabolism%20v4.pdf]</ref> During times of low glucose (such as [[fasting]]), the brain will primarily use [[ketone bodies]] for fuel with a smaller requirement for glucose. The brain can also utilize lactate during exercise.<ref>{{cite journal |url=http://www.fasebj.org/cgi/content/abstract/22/10/3443 |title=Lactate fuels the human brain during exercise |last1=Quistorff |first1=Bjørn |last2=Secher |first2=Niels |last3=Van Lieshout |first3=Johanne |date=July 24, 2008 |work=[[The FASEB Journal]]|doi=10.1096/fj.08-106104 |accessdate=May 9, 2011}}</ref> The brain does not store any glucose in the form of [[glycogen]], in contrast, for example, to [[skeletal muscle]].

==Additional images==
{{Commons category| Brain}}
<gallery>
File:Brain - Lobes.png
File:BrainLobesLabelled.jpg
File:Embryonicbrain.png
File:Gray720.png
File:Human brain midsagittal cut .JPG
</gallery>

== See also ==
{{Portalbox|Neuroscience|Thinking}}
* [[Cephalic disorders]]
* [[Cephalization]]
* [[Common misconceptions about the brain]]
* [[History of neuroscience]]
* [[Lateralization of brain function]]
* [[List of neuroscience databases]]
* [[List of regions in the human brain]]
* [[Lobes of the brain]]
* [[Neural development in humans]]
* [[Neuroanatomy]]
* [[Neuroanthropology]]
* [[Neuroscience]]
* [[Philosophy of mind]]
* [[10% of brain myth]]

== Notes ==
{{Reflist|30em}}

==References==
{{Refbegin|2}}

*<cite id="refAndrews">{{cite book
| last = Andrews
| first = DG
| title = Neuropsychology
| publisher = Psychology Press
| year = 2001
| url = http://books.google.com/?id=kiCtU8wBTfwC
| isbn = 9781841691039
}}</cite>

*<cite id="refBuxton">{{cite book
| last = Buxton
| first = RB
| title = An Introduction to Functional Magnetic Resonance Imaging: Principles and Techniques
| publisher = Cambridge University Press
| year = 2002
| url = http://books.google.com/?id=FordF5AN9vwC
| isbn = 9780521581134
}}</cite>

* Campbell, Neil A. and Jane B. Reece. (2005). ''Biology''. Benjamin Cummings. ISBN 0-8053-7171-0

*<cite id="refCosgrove">{{cite journal
| last = Cosgrove
| first = KP
| coauthors = Mazure CM, Staley JK
| url = http://linkinghub.elsevier.com/retrieve/pii/S0006322307001989
| title = Evolving knowledge of sex differences in brain structure, function, and chemistry.
| year = 2007
| journal = Biol Psychiat
| volume = 62
| pages = 847–55
| pmid = 17544382
| doi = 10.1016/j.biopsych.2007.03.001
| issue = 8
| pmc = 2711771
}}</cite>

*<cite id="refFisch">{{cite book
| last = Fisch
| first = BJ
| coauthors = Spehlmann R
| year = 1999
| title = Fisch and Spehlmann's EEG Primer: Basic Principles of Digital and Analog EEG.
| publisher = Elsevier Health Sciences
| isbn = 9780444821485
| url = http://books.google.com/?id=YMHsluy4QygC
}}</cite>

*<cite id="refGray">{{cite book
| last = Gray
| first = Peter
| title = Psychology
| publisher = Worth Publishers
| year = 2002
| edition = 4th
| isbn = 0716751623
}}</cite>

*<cite id="refPrinciples">{{cite book
| last = Kandel
| first = ER
| coauthors = Schwartz JH, Jessel TM
| title = Principles of Neural Science
| year = 2000
| publisher = McGraw-Hill Professional
| isbn = 9780838577011
| url =
}}</cite>

* McGilchrist, Ian (2010), ''The Master and His Emissary''. Yale.

*<cite id="refCarpenter">{{cite book
| title = Carpenter's Human Neuroanatomy
| last=Parent
| first=A
| coauthors=Carpenter MB
| publisher = Williams & Wilkins
| year = 1995
| isbn = 9780683067521
| url = http://books.google.com/?id=IJ5pAAAAMAAJ
}}</cite>

*<cite id="refPreissl">{{cite book
| last = Preissl
| first = H
| year = 2005
| title = Magnetoencephalography
| publisher = Academic Press
| isbn = 9780123668691
| url = http://books.google.com/?id=ElTJAAAACAAJ
}}</cite>

* Ramachanandran, V S (2011), ''The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human''. [[W. W. Norton & Company]].

* Simon, Seymour (1999). ''The Brain''. HarperTrophy. ISBN 0-688-17060-9

* Thompson, Richard F. (2000). ''The Brain: An Introduction to Neuroscience''. Worth Publishers. ISBN 0-7167-3226-2

*<cite id="refToro">{{cite journal
| last = Toro
| first = R
| coauthors = Perron M, Pike B, Richer L. Veillette S, Pausova Z, Paus T
| year = 2008
| title = Brain size and folding of the human cerebral cortex.
| volume = 18
| pages = 2352–7
| url = http://cercor.oxfordjournals.org/cgi/content/abstract/18/10/2352
| pmid = 18267953
| doi = 10.1093/cercor/bhm261
| issue = 10
| journal = Cerebral cortex (New York, N.Y. : 1991)
}}</cite>

*<cite id="refVanderwolf1978">{{cite pmid|564358}}</cite>

{{Refend}}

==External links==
* [http://www.med.harvard.edu/AANLIB/home.html The Whole Brain Atlas]
* [http://primate-brain.org High-Resolution Cytoarchitectural Primate Brain Atlases]
* [http://faculty.washington.edu/chudler/facts.html Brain Facts and Figures]
* [http://www.healthline.com/human-body-maps/brain Interactive Human Brain 3D Tool]

{{Organ systems}}
{{Footer Neuropsychology}}
{{nervous system}}
{{Medulla}}
{{Pons}}
{{Mesencephalon}}
{{Cerebellum}}
{{Diencephalon}}
{{Telencephalon}}

{{DEFAULTSORT:Human Brain}}
[[Category:Brain]]

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[[cs:Lidský mozek]]
[[es:Cerebro humano]]
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[[is:Mannsheilinn]]
[[ka:ადამიანის თავის ტვინი]]
[[hu:Emberi agy]]
[[nl:Menselijke hersenen]]
[[pl:Mózgowie człowieka]]
[[pt:Cérebro humano]]
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[[zh:人腦]]

Attention versus memory in prefrontal cortex

2011-09-13T13:12:58Z

PhineasG:

{{Refimprove|date=July 2009}}
A widely accepted theory regarding the function of the brain's [[prefrontal cortex]] is that it serves as a store of [[short-term memory]]. This idea was first formulated by Jacobsen, who reported in 1935 that damage to the primate prefrontal cortex caused short-term memory deficits. [[Karl H. Pribram|Karl Pribram]] and colleagues (1952) identified the part of the prefrontal cortex responsible for this deficit as [[Brodmann area|area]] [[Brodmann area 46|46]], also known as the [[dorsolateral prefrontal cortex]] (dlPFC). More recently, [[Patricia Goldman-Rakic|Goldman-Rakic]] and colleagues (1993) evoked short-term memory loss in localized regions of space by temporary inactivation of portions of the dlPFC. Once the concept of [[working memory]] (see also [[Baddeley's model of working memory]]) was established in contemporary neuroscience by Baddeley (1986), these neuropsychological findings contributed to the theory that the prefrontal cortex implements working memory and, in some extreme formulations, only working memory. In the 1990s this theory developed a wide following, and it became the predominant theory of PF function, especially for nonhuman primates. The concept of working memory used by proponents of this theory focused mostly on the short-term maintenance of information, and rather less on the manipulation or monitoring of such information or on the use of that information for decisions. Consistent with the idea that the prefrontal cortex functions predominantly in maintenance memory, delay-period activity in the PF has often been interpreted as a memory trace. (The phrase "delay-period activity" applies to neuronal activity that follows the transient presentation of an instruction cue and persists until a subsequent "go" or "trigger" signal.)

To explore alternative interpretations of delay-period activity in the prefrontal cortex, Lebedev et al. (2004) investigated the discharge rates of single prefrontal neurons as monkeys attended to a stimulus marking one location while remembering a different, unmarked location. Both locations served as potential targets of a [[saccadic eye movement]]. Although the task made intensive demands on short-term memory, the largest proportion of prefrontal neurons represented attended locations, not remembered ones. These findings showed that short-term memory functions cannot account for all, or even most, delay-period activity in the part of the prefrontal cortex explored. The authors suggested that prefrontal activity during the delay-period contributes more to the process of attentional selection (and [[selective attention]]) than to memory storage.

[[Image:Attention_vs_memory.gif]]

''Lebedev et al. experiment that dissociated representation of spatial [[attention]] from representation of [[spatial memory]] in [[prefrontal cortex]]''

==Further reading==
* Baddeley A. (1986) Working memory. Oxford: Oxford University Press. 289 p.
* Funahashi S., Bruce C.J., Goldman-Rakic P.S. (1993a) Dorsolateral prefrontal lesions and oculomotor delayed-response performance: Evidence for mnemonic “scotomas.”. J Neurosci 13: 1479–1497.
* Jacobsen C.F. (1936) Studies of cerebral function in primates. I. The functions of the frontal associations areas in monkeys. Comp Psychol Monogr 13: 3–60.
* Lebedev M.A., Messinger A., Kralik J.D., Wise S.P. (2004) [http://biology.plosjournals.org/perlserv/?request=get-document&doi=10%2E1371%2Fjournal%2Epbio%2E0020365 Representation of attended versus remembered locations in prefrontal cortex.] PLoS Biology, 2: 1919-1935.
* Postle B.R., Druzgal T.J., D'Esposito M. (2003) Seeking the neural substrates of visual working memory storage. Cortex 39: 927–946.
* Pribram K.H., Mishkin M., Rosvold H.E., Kaplan S.J. (1952) Effects of delayed-response performance of lesions of dorsolateral and ventromedial frontal cortex of baboons. J Comp Physiol Psychol 45: 565–575.

[[Category:Cognitive neuroscience]]
[[Category:Attention]]
[[Category:Memory]]
[[Category:Cognition]]
[[Category:Dyslexia]]

Working memory

2011-09-13T13:11:31Z

PhineasG: /* Physiology and Psychopharmacology */

'''Working memory''' is the ability to actively hold information in the mind needed to do complex tasks such as reasoning, comprehension and learning. Working memory tasks are those that require the goal-oriented active monitoring or manipulation of information or behaviors in the face of interfering processes and distractions. The cognitive processes involved include the [[Executive functions|executive]] and [[attention]] control of [[short-term memory]] which provide for the interim integration, processing, disposal, and retrieval of information. Working memory is a theoretical concept central both to [[cognitive psychology]] and [[neuroscience]].

Theories exist both regarding the theoretical structure of working memory and the role of specific parts of the brain involved in working memory. Research identifies the [[frontal cortex]], [[parietal cortex]], [[anterior cingulate]], and parts of the [[basal ganglia]] as crucial. The neural basis of working memory has been derived from [[lesion]] experiments in animals and [[functional imaging]] upon humans.

==History==
The term "working memory" was coined by [[George Armitage Miller|Miller]], [[Eugene Galanter|Galanter]], and [[Karl H. Pribram|Pribram]],<ref>Miller, GA., Galanter, E. & Pribram, KH. (1960) "Plans and the Structure of Behavior." Holt, Rinehart & Winston, New York.{{Page needed|date=September 2010}}</ref><ref>{{Cite journal|author=Baddeley A |title=Working memory: looking back and looking forward |journal=Nature Reviews. Neuroscience |volume=4 |issue=10 |pages=829–39 |year=2003 |month=October |pmid=14523382 |doi=10.1038/nrn1201}}</ref> and was used in the 1960s in the context of theories that likened the mind to a computer. [[Atkinson–Shiffrin memory model|Atkinson and Shiffrin]] (1968)<ref>Atkinson, R. C., & Shiffrin, R. M. (1968). Human memory: A proposed system and its control processes. In K. W. Spence & J. T. Spence (Eds.), The psychology of learning and motivation (Vol. 2, pp. 89–195). New York: Academic Press.</ref> also used this term, "working memory" (p. 92) to describe their "short-term store." What we now call working memory was referred to as a "short-term store" or [[short-term memory]], primary memory, immediate memory, operant memory, or provisional memory.<ref>Fuster, J. M. (1997). The Prefrontal Cortex: Anatomy, physiology, and neuropsychology of the frontal lobe (2 ed.): Lippincott, Williams & Wilkins{{Page needed|date=September 2010}}</ref> Short-term memory is the ability to remember information over a brief period of time (in the order of seconds). Most theorists today use the concept of working memory to replace or include the older concept of short-term memory, thereby marking a stronger emphasis on the notion of manipulation of information instead of passive maintenance.

The earliest mention of experiments on the neural basis of working memory can be traced back to over 100 years ago, when [[Eduard Hitzig|Hitzig]] and [[David Ferrier|Ferrier]] described [[ablation]] experiments of the [[prefrontal cortex]] (PFC), they concluded that the frontal cortex was important for cognitive rather than sensory processes.<ref name=Fuster1>{{Cite book|last1= Fuster|first1= Joaquin |title= The prefrontal cortex |page= 126 |url= http://books.google.com/?id=zuZlvNICdhUC&pg=PT140&dq=%22different+investigators,+the+variability+of%22&cd=1#v=onepage&q=%22different%20investigators%2C%20the%20variability%20of%22 |edition= 4 |year= 2008 |publisher= Elsevier |location= Oxford UK |isbn= 9780123736444}}</ref> In 1935 and 1936, Carlyle Jacobsen and colleagues were the first to show the deleterious effect of prefrontal ablation on delayed response.<ref name=Fuster1/><ref name=Benton>{{Cite book|last1= Benton|first1= A.L|editor1-first= Harvey S.|editor1-last= Levin|editor2-first= Howard M.|editor2-last= Eisenberg|editor3-first= Arthur L.|editor3-last= Benton|title= Frontal lobe function and dysfunction|url= http://books.google.com/?id=9b1htO0V0rwC&pg=PA19&lpg=PA19&dq=Jacobsen++prefrontal+ablation&q=Jacobsen%20%20prefrontal%20ablation|year= 1991|publisher= Oxford University Press|location= New York|isbn= 0-19-506284-1|page= 19|chapter= The prefrontal region:Its early history}}</ref>

==Theories==
There have been numerous models proposed regarding how working memory functions, both anatomically and cognitively. Of those, three that are well known are summarized below.

===Baddeley and Hitch===
{{Main|Baddeley's model of working memory}}

[[Alan Baddeley|Baddeley]] and Hitch (1974)<ref>Baddeley, A.D., Hitch, G.J.L (1974). Working Memory, In G.A. Bower (Ed.), ''The psychology of learning and motivation: advances in research and theory'' (Vol. 8, pp. 47–89), New York: Academic Press.</ref> introduced and made popular the [[Baddeley's model of working memory|multicomponent model of working memory]]. This theory proposes that two "slave systems" are responsible for short-term maintenance of information, and a "central executive" is responsible for the supervision of information integration and for coordinating the slave systems. One slave system, the [[phonological loop]] (PL), stores phonological information (that is, the sound of language) and prevents its decay by continuously articulating its contents, thereby refreshing the information in a [[memory rehearsal|rehearsal]] loop. It can, for example, maintain a seven-digit telephone number for as long as one repeats the number to oneself again and again. The other slave system, the [[visuo-spatial sketch pad]] (VSSP), stores visual and spatial information. It can be used, for example, for constructing and manipulating visual images, and for the representation of mental maps. The sketch pad can be further broken down into a visual subsystem (dealing with, for instance, shape, colour, and texture), and a spatial subsystem (dealing with location). The central executive (see [[executive system]]) is, among other things, responsible for directing [[attention]] to relevant information, suppressing irrelevant information and inappropriate actions, and for coordinating cognitive processes when more than one task must be done at the same time.

Baddeley (2000) extended the model by adding a fourth component, the episodic buffer, which holds representations that integrate phonological, visual, and spatial information, and possibly information not covered by the slave systems (e.g., semantic information, musical information). The component is episodic because it is assumed to bind information into a unitary episodic representation. The episodic buffer resembles Tulving's concept of [[episodic memory]], but it differs in that the episodic buffer is a temporary store.

===Cowan===
[[Nelson Cowan|Cowan]]<ref>Cowan, N. (1995). Attention and memory: An integrated framework. New York: Oxford University Press.{{Page needed|date=September 2010}}</ref><ref>Cowan, N. (2005). Working memory capacity. New York, NY: Psychology Press{{Page needed|date=September 2010}}</ref> regards working memory not as a separate system, but as a part of [[long-term memory]]. Representations in working memory are a subset of the representations in long-term memory. Working memory is organized into two embedded levels. The first level consists of long-term memory representations that are activated. There can be many of these, there is no limit to activation of representations in long-term memory. The second level is called the focus of attention. The focus is regarded as capacity limited and holds up to four of the activated representations.

Oberauer<ref>{{Cite journal|author=Oberauer K |title=Access to information in working memory: exploring the focus of attention |journal=Journal of Experimental Psychology. Learning, Memory, and Cognition |volume=28 |issue=3 |pages=411–21 |year=2002 |month=May |pmid=12018494 |doi=10.1037/0278-7393.28.3.411}}</ref> has extended the Cowan model by adding a third component, a more narrow focus of attention that holds only one chunk at a time. The one-element focus is embedded in the four-element focus and serves to select a single chunk for processing. For example, you can hold four digits in mind at the same time in Cowan's "focus of attention". Now imagine that you wish to perform some process on each of these digits, for example, adding the number two to each digit. Separate processing is required for each digit, as most individuals can not perform several mathematical processes in parallel. Oberauer's attentional component selects one of the digits for processing, and then shifts the attentional focus to the next digit, continuing until all of the digits have been processed.

===Ericsson and Kintsch===
Ericsson and Kintsch (1995) have argued that we use skilled memory in most everyday tasks. Tasks such as [[Reading (process)|reading]], for instance, require to maintain in memory much more than seven chunks - with a capacity of only seven chunks our working memory would be full after a few sentences, and we would never be able to understand the complex relations between thoughts expressed in a novel or a scientific text. We accomplish this by storing most of what we read in long-term memory, linking them together through retrieval structures. We need to hold only a few concepts in working memory, which serve as cues to retrieve everything associated to them by the retrieval structures. [[Anders Ericsson]] and Walter Kintsch refer to this set of processes as "long-term working memory". Retrieval structures vary according to the domain of expertise, yet as suggested by Gobet<ref>{{Cite journal|author=Gobet F |title=Some shortcomings of long-term working memory |journal=British Journal of Psychology |volume=91 |issue=Pt 4 |pages=551–70 |year=2000 |month=November |pmid=11104178 |doi=10.1348/000712600161989}}</ref> they can be categorized in three typologies: generic retrieval structures, domain knowledge retrieval structures and the episodic text structures. The first corresponds to Ericsson and Kintsch's 'classic' retrieval structure and the second to the elaborated memory structure. The first kind of structure is developed deliberately and is arbitrary (for example, the method of loci), the second one is similar to patterns and schemas and the last one takes place exclusively during text comprehension. Concerning this last typology, Kintsch, Patel and Ericsson<ref>{{Cite journal|first1=Walter |last1=Kintsch |first2=Vimla L. |last2=Patel |first3=K. Anders |last3=Ericsson |year=1999 |title=The role of long-term working memory in text comprehension |journal=Psychologia |volume=42 |issue=4 |pages=186–98}}</ref> consider that every reader is able to form an episodic text structure during text comprehension, if the text is well written and if the content is familiar.

==Capacity==
Working memory is generally considered to have limited capacity. The earliest quantification of the capacity limit associated with short-term memory was the "[[The Magical Number Seven, Plus or Minus Two|magical number seven]]" suggested by Miller (1956).<ref name="miller">{{Cite journal|author=Miller GA |title=The magical number seven plus or minus two: some limits on our capacity for processing information |journal=Psychological Review |volume=63 |issue=2 |pages=81–97 |year=1956 |month=March |pmid=13310704 |doi=10.1037/h0043158}} Republished: {{Cite journal|author=Miller GA |title=The magical number seven, plus or minus two: some limits on our capacity for processing information. 1956 |journal=Psychological Review |volume=101 |issue=2 |pages=343–52 |year=1994 |month=April |pmid=8022966 |doi=10.1037/0033-295X.101.2.343}}</ref> He noticed that the memory span of young adults was around seven elements, called chunks, regardless whether the elements were digits, letters, words, or other units. Later research revealed that span does depend on the category of chunks used (e.g., span is around seven for digits, around six for letters, and around five for words), and even on features of the [[chunking (psychology)|chunks]] within a category. For instance, span is lower for long words than for short words. In general, memory span for verbal contents (digits, letters, words, etc.) strongly depends on the time it takes to speak the contents aloud, and on the lexical status of the contents (i.e., whether the contents are words known to the person or not).<ref>{{Cite journal|first1=Charles |last1=Hulme |first2=Steven |last2=Roodenrys |first3=Gordon |last3=Brown |first4=Robin |last4=Mercer |month=November |year=1995 |title=The role of long-term memory mechanisms in memory span |journal=British Journal of Psychology |volume=86 |issue=4 |pages=527–36 |url=http://psycnet.apa.org/?fa=main.doiLanding&uid=1996-29539-001 |doi=10.1111/j.2044-8295.1995.tb02570.x}}</ref> Several other factors also affect a person's measured span, and therefore it is difficult to pin down the capacity of short-term or working memory to a number of chunks. Nonetheless, Cowan (2001)<ref>{{Cite journal|first1=Nelson |last1=Cowan |year=2001 |title=The magical number 4 in short-term memory: A reconsideration of mental storage capacity |journal=Behavioral and Brain Sciences |volume=24 |pages=87–185 |doi=10.1017/S0140525X01003922 |pmid=11515286}}</ref> has proposed that working memory has a capacity of about four chunks in young adults (and fewer in children and old adults).

Whereas most adults can repeat about seven digits in correct order, some individuals have shown impressive enlargements of their digit span{{ndash}} up to 80 digits. This feat is possible by extensive training on an encoding strategy by which the digits in a list are grouped (usually in groups of three to five) and these groups are encoded as a single unit (a chunk). To do so one must be able to recognize the groups as some known string of digits. One person studied by K. Anders Ericsson and his colleagues, for example, used his extensive knowledge of racing times from the history of sports. Several such chunks can then be combined into a higher-order chunk, thereby forming a hierarchy of chunks. In this way, only a small number of chunks at the highest level of the hierarchy must be retained in working memory. At retrieval, the chunks are unpacked again. That is, the chunks in working memory act as retrieval cues that point to the digits that they contain. It is important to note that practicing memory skills such as these does not expand working memory capacity proper. This can be shown by using different materials - the person who could recall 80 digits was not exceptional when it came to recalling words.

===Measures and correlates===
Working memory capacity can be tested by a variety of tasks. A commonly used measure is a dual-task paradigm combining a [[memory span]] measure with a concurrent processing task, sometimes referred to as "complex span". Daneman and Carpenter invented the first version of this kind of task, the "[[reading span]]", in 1980.<ref>{{Cite journal|first1=Meredyth |last1=Daneman |first2=Patricia A. |last2=Carpenter |month=August |year=1980 |title=Individual differences in working memory and reading |journal=Journal of Verbal Learning & Verbal Behavior |volume=19 |issue=4 |pages=450–66 |doi=10.1016/S0022-5371(80)90312-6}}</ref> Subjects read a number of sentences (usually between 2 and 6) and try to remember the last word of each sentence. At the end of the list of sentences, they repeat back the words in their correct order. Other tasks that don't have this dual-task nature have also been shown to be good measures of working memory capacity.<ref>{{Cite journal|doi=10.1016/S0191-8869(99)00251-2 |title=Working memory capacity — facets of a cognitive ability construct |month=December |year=2000 |first1=K. |last1=Oberauer |first2=H.-M. |last2=Sus |first3=R. |last3=Schulze |first4=O |last4=Wilhelm |first5=W. W. |last5=Wittmann |journal=Personality and Individual Differences |volume=29 |issue=6 |pages=1017–45}}</ref> The question of what features a task must have to qualify as a good measure of working memory capacity is a topic of ongoing research.

Measures of working-memory capacity are strongly related to performance in other complex cognitive tasks such as reading comprehension, problem solving, and with any measures of the [[intelligence quotient]].<ref>{{Cite journal|author=Conway AR, Kane MJ, Engle RW |title=Working memory capacity and its relation to general intelligence |journal=Trends in Cognitive Sciences |volume=7 |issue=12 |pages=547–52 |year=2003 |month=December |pmid=14643371 |doi=10.1016/j.tics.2003.10.005}}</ref> Some researchers have argued<ref>{{Cite journal|author=Engle RW, Tuholski SW, Laughlin JE, Conway AR |title=Working memory, short-term memory, and general fluid intelligence: a latent-variable approach |journal=Journal of Experimental Psychology: General |volume=128 |issue=3 |pages=309–31 |year=1999 |month=September |pmid=10513398 |doi=10.1037/0096-3445.128.3.309}}</ref> that working memory capacity reflects the efficiency of executive functions, most notably the ability to maintain a few task-relevant representations in the face of distracting irrelevant information. The tasks seem to reflect individual differences in ability to focus and maintain attention, particularly when other events are serving to capture attention. These effects seem to be a function of frontal brain areas.<ref name="Kane MJ, Engle RW 2002 637–71">{{Cite journal|doi=10.3758/BF03196323|author=Kane MJ, Engle RW |title=The role of prefrontal cortex in working-memory capacity, executive attention, and general fluid intelligence: an individual-differences perspective |journal=Psychonomic Bulletin & Review |volume=9 |issue=4 |pages=637–71 |year=2002 |month=December |pmid=12613671 |url=http://pbr.psychonomic-journals.org/cgi/pmidlookup?view=long&pmid=12613671}}</ref>

Others have argued that the capacity of working memory is better characterized as the ability to mentally form relations between elements, or to grasp relations in given information. This idea has been advanced, among others, by Graeme Halford, who illustrated it by our limited ability to understand statistical interactions between variables.<ref>{{Cite journal|author=Halford GS, Baker R, McCredden JE, Bain JD |title=How many variables can humans process? |journal=Psychological Science |volume=16 |issue=1 |pages=70–6 |year=2005 |month=January |pmid=15660854 |doi=10.1111/j.0956-7976.2005.00782.x}}</ref> These authors asked people to compare written statements about the relations between several variables to graphs illustrating the same or a different relation, as in the following sentence: "If the cake is from France, then it has more sugar if it is made with chocolate than if it is made with cream, but if the cake is from Italy, then it has more sugar if it is made with cream than if it is made of chocolate." This statement describes a relation between three variables (country, ingredient, and amount of sugar), which is the maximum most individuals can understand. The capacity limit apparent here is obviously not a memory limit (all relevant information can be seen continuously) but a limit on how many relationships are discerned simultaneously.

===Experimental studies of working memory capacity===
====Different approaches====
There are several hypotheses about the nature of the capacity limit. One is that there is a limited pool of cognitive resources needed to keep representations active and thereby available for processing, and for carrying out processes.<ref>{{Cite journal|author=Just MA, Carpenter PA |title=A capacity theory of comprehension: individual differences in working memory |journal=Psychological Review |volume=99 |issue=1 |pages=122–49 |year=1992 |month=January |pmid=1546114 |doi=10.1037/0033-295X.99.1.122}}</ref> Another hypothesis is that memory traces in working memory decay within a few seconds, unless refreshed through rehearsal, and because the speed of rehearsal is limited, we can maintain only a limited amount of information.<ref>{{Cite journal|doi=10.3758/BF03198549|author=Towse JN, Hitch GJ, Hutton U |title=On the interpretation of working memory span in adults |journal=Memory & Cognition |volume=28 |issue=3 |pages=341–8 |year=2000 |month=April |pmid=10881551}}</ref> Yet another idea is that representations held in working memory capacity interfere with each other.<ref>{{Cite journal|author=Waugh NC, Norman DA |title=Primary Memory |journal=Psychological Review |volume=72 |issue= |pages=89–104 |year=1965 |month=March |pmid=14282677 |doi=10.1037/h0021797}}</ref>

There are several forms of [[Interference theory|interference]] discussed by theorists. One of the oldest ideas is that new items simply replace older ones in working memory. Another form of interference is retrieval competition. For example, when the task is to remember a list of 7 words in their order, we need to start recall with the first word. While trying to retrieve the first word, the second word, which is represented in close proximity, is accidentally retrieved as well, and the two compete for being recalled. Errors in serial recall tasks are often confusions of neighboring items on a memory list (so-called transpositions), showing that retrieval competition plays a role in limiting our ability to recall lists in order, and probably also in other working memory tasks. A third form of interference assumed by some authors is feature overwriting.<ref>{{Cite journal|doi=10.1016/j.jml.2006.08.009 |title=A formal model of capacity limits in working memory |month=November |year=2006 |first1=Klaus |last1=Oberauer |first2=Reinhold |last2=Kliegl |journal=Journal of Memory and Language |volume=55 |issue=4 |pages=601–26}}</ref> The idea is that each word, digit, or other item in working memory is represented as a bundle of features, and when two items share some features, one of them steals the features from the other. The more items are held in working memory, and the more their features overlap, the more each of them will be degraded by the loss of some features.

====Time-based resource sharing model====
The theory most successful so far in explaining experimental data on the interaction of maintenance and processing in working memory is the "time-based resource sharing model".<ref>{{Cite journal|author=Barrouillet P, Bernardin S, Camos V |title=Time constraints and resource sharing in adults' working memory spans |journal=Journal of Experimental Psychology. General |volume=133 |issue=1 |pages=83–100 |year=2004 |month=March |pmid=14979753 |doi=10.1037/0096-3445.133.1.83}}</ref> This theory assumes that representations in working memory decay unless they are refreshed. Refreshing them requires an attentional mechanism that is also needed for any concurrent processing task. When there are small time intervals in which the processing task does not require attention, this time can be used to refresh memory traces. The theory therefore predicts that the amount of forgetting depends on the temporal density of attentional demands of the processing task - this density is called "cognitive load". The cognitive load depends on two variables, the rate at which the processing task requires individual steps to be carried out, and the duration of each step. For example, if the processing task consists of adding digits, then having to add another digit every half second places a higher cognitive load on the system than having to add another digit every two seconds. Adding larger digits takes more time than adding smaller digits, and therefore cognitive load is higher when larger digits must be added. In a series of experiments, Barrouillet and colleagues have shown that memory for lists of letters depends on cognitive load, but not on the number of processing steps (a finding that is difficult to explain by an interference hypothesis) and not on the total time of processing (a finding difficult to explain by a simple decay hypothesis). One difficulty for the time-based resource-sharing model, however, is that the similarity between memory materials and materials processed also affects memory accuracy.

====Limitations====
None of these hypotheses can explain the experimental data entirely. The resource hypothesis, for example, was meant to explain the trade-off between maintenance and processing: The more information must be maintained in working memory, the slower and more error prone concurrent processes become, and with a higher demand on concurrent processing memory suffers. This trade-off has been investigated by tasks like the reading-span task described above. It has been found that the amount of trade-off depends on the similarity of the information to be remembered and the information to be processed. For example, remembering numbers while processing spatial information, or remembering spatial information while processing numbers, impair each other much less than when material of the same kind must be remembered and processed.<ref>{{Cite journal|doi=10.1016/j.jml.2006.07.009 |title=The relationship between processing and storage in working memory span: Not two sides of the same coin |month=February |year=2007 |first1=Yukio |last1=Maehara |first2=Satoru |last2=Saito |journal=Journal of Memory and Language |volume=56 |issue=2 |pages=212–228}}</ref> Also, remembering words and processing digits, or remembering digits and processing words, is easier than remembering and processing materials of the same category.<ref>{{Cite journal|doi=10.1076/anec.6.2.99.784 |title=Selection from Working Memory: on the Relationship between Processing and Storage Components |month=June |year=1999 |last1=Li |first1=Karen Z.H. |journal=Aging, Neuropsychology, and Cognition |volume=6 |issue=2 |pages=99–116}}</ref> These findings are also difficult to explain for the decay hypothesis, because decay of memory representations should depend only on how long the processing task delays rehearsal or recall, not on the content of the processing task. A further problem for the decay hypothesis comes from experiments in which the recall of a list of letters was delayed, either by instructing participants to recall at a slower pace, or by instructing them to say an irrelevant word once or three times in between recall of each letter. Delaying recall had virtually no effect on recall accuracy.<ref>{{Cite journal|doi=10.3758/BF03196705|author=Lewandowsky S, Duncan M, Brown GD |title=Time does not cause forgetting in short-term serial recall |journal=Psychonomic Bulletin & Review |volume=11 |issue=5 |pages=771–90 |year=2004 |month=October |pmid=15732687 |url=http://pbr.psychonomic-journals.org/cgi/pmidlookup?view=long&pmid=15732687}}</ref><ref>{{Cite journal|author=Oberauer K, Lewandowsky S |title=Forgetting in immediate serial recall: decay, temporal distinctiveness, or interference? |journal=Psychological Review |volume=115 |issue=3 |pages=544–76 |year=2008 |month=July |pmid=18729591 |doi=10.1037/0033-295X.115.3.544}}</ref> The [[Interference theory]] seems to fare best with explaining why the similarity between memory contents and the contents of concurrent processing tasks affects how much they impair each other. More similar materials are more likely to be confused, leading to retrieval competition, and they have more overlapping features, leading to more feature overwriting. One experiment directly manipulated the amount of overlap of phonological features between words to be remembered and other words to be processed.<ref>{{Cite journal|author=Lange EB, Oberauer K |title=Overwriting of phonemic features in serial recall |journal=Memory |volume=13 |issue=3-4 |pages=333–9 |year=2005 |pmid=15948618 |doi=10.1080/09658210344000378}}</ref> Those to-be-remembered words that had a high degree of overlap with the processed words were recalled worse, lending some support to the idea of interference through feature overwriting.

==Development==

The capacity of working memory increases gradually over childhood <ref name="ReferenceA">{{cite journal | doi = 10.1037/0012-1649.40.2.177 | last1 = Gathercole | first1 = S. E. | last2 = Pickering | first2 = S. J. | last3 = Ambridge | first3 = B. | last4 = Wearing | first4 = H. | year = 2004 | title = The structure of working memory from 4 to 15 years of age | url = | journal = Developmental Psychology | volume = 40 | issue = 2| pages = 177–190 | pmid = 14979759 }}</ref> and declines gradually in old age.<ref>{{cite journal | doi = 10.1037/0894-4105.8.4.535 | last1 = Salthouse | first1 = T. A. | year = 1994 | title = The aging of working memory | url = | journal = Neuropsychology | volume = 8 | issue = | pages = 535–543 }}</ref>

===Childhood===
{{Main|Neo-Piagetian theories of cognitive development}}

Measures of performance on tests of working memory increase continuously between early childhood and adolescence, while the structure of correlations between different tests remains largely constant.<ref name="ReferenceA"/> Thus, the development of working memory can be described as quantitative growth rather than a qualitative change. Starting with work in the Neo-Piagetian tradition,<ref>{{cite journal | doi = 10.1016/0001-6918(70)90108-3 | last1 = Pascual-Leone | first1 = J. | year = 1970 | title = A mathematical model for the transition rule in Piaget's developmental stages | url = | journal = Acta Psychologica | volume = 32 | issue = | pages = 301–345 }}</ref><ref>Case, R. (1985). Intellectual development. Birth to adulthood. New York: Academic Press.</ref> theorists have argued that the growth of working-memory capacity is a major driving force of cognitive development. This hypothesis has received substantial empirical support from studies showing that the capacity of working memory is a strong predictor of cognitive abilities in childhood.<ref>Jarrold, C., & Bayliss, D. M. (2007). Variation in working memory due to typical and atypical development. In A. R. A. Conway, C. Jarrold, M. J. Kane, A. Miyake & J. N. Towse (Eds.), Variation in working memory (pp. 137–161). New York: Oxford University Press.</ref> Particularly strong evidence for a role of working memory for development comes from a longitudinal study showing that working-memory capacity at one age predicts reasoning ability at a later age <ref>{{cite journal | doi = 10.1111/j.1467-9280.2007.01895.x | last1 = Kail | first1 = R. | year = 2007 | title = Longitudinal evidence that increases in processing speed and working memory enhance children's reasoning | url = | journal = Psychological Science | volume = 18 | issue = 4| pages = 312–313 | pmid = 17470254 }}</ref> Studies in the Neo-Piagetian tradition have added to this picture by analyzing the complexity of cognitive tasks in terms of the number of items or relations that have to be considered simultaneously for a solution. Across a broad range of tasks, children manage task versions of the same level of complexity at about the same age, consistent with the view that working memory capacity limits the complexity they can handle at a given age <ref>{{cite journal | doi = 10.1016/S0010-0285(02)00002-6 | last1 = Andrews | first1 = G. | last2 = Halford | first2 = G. S. | year = 2002 | title = A cognitive complexity metric applied to cognitive development | url = | journal = Cognitive Psychology | volume = 45 | issue = 2| pages = 153–219 | pmid = 12528901 }}</ref>

===Aging===
Working memory is among the cognitive functions most sensitive to decline in old age.<ref>Hertzog, C., Dixon, R. A., Hultsch, D. F., & MacDonald, S. W. S. (2003). Latent change models of adult cognition: Are changes in processing speed and working memory associated with changes in episodic memory? Psychology and Aging, 18, 755–769.</ref><ref name="Park, D. C. 2002">Park, D. C., Lautenschlager, G., Hedden, T., Davidson, N. S., Smith, A. D., & Smith, P. K. (2002). Models of visuospatial and verbal memory across the adult life span. Psychology & Aging, 17, 299–320.</ref> Several explanations have been offered for this decline in psychology. One is the processing speed theory of cognitive aging by Tim Salthouse.<ref>{{cite journal | doi = 10.1037/0033-295X.103.3.403 | last1 = Salthouse | first1 = T. A. | year = 1996 | title = The processing speed theory of adult age differences in cognition | url = | journal = Psychological Review | volume = 103 | issue = 3| pages = 403–428 | pmid = 8759042 }}</ref> Based on the finding of general slowing of cognitive processes as we grow older, Salthouse argues that slower processing leaves more time for working-memory contents to decay, thus reducing effective capacity. However, the decline of working-memory capacity cannot be entirely attributed to slowing because capacity declines more in old age than speed.<ref name="Park, D. C. 2002"/><ref>{{cite journal | doi = 10.1016/0010-0277(95)00689-3 | last1 = Mayr | first1 = U. | last2 = Kliegl | first2 = R. | last3 = Krampe | first3 = R. T. | year = 1996 | title = Sequential and coordinative processing dynamics in figural transformation across the life span | url = | journal = Cognition | volume = 59 | issue = 1| pages = 61–90 | pmid = 8857471 }}</ref> Another proposal is the inhibition hypothesis advanced by Lynn Hasher and Rose Zacks.<ref>Hasher, L., & Zacks, R. T. (1988). Working memory, comprehension, and aging: A review and new view. In G. H.Bower (Ed.), ''The psychology of learning and motivation'', ''Vol. 22'', (pp. 193–225). New York: Academic Press.</ref> This theory assumes a general deficit in old age in the ability to inhibit irrelevant, or no-longer relevant, information. Therefore, working memory tends to be cluttered with irrelevant contents that reduce the effective capacity for relevant content. The assumption of an inhibition deficit in old age has received much empirical support <ref>Hasher, L., Zacks, R. T., & May, C. P. (1999). Inhibitory control, circadian arousal, and age. In D. Gopher & A. Koriat (Eds.), Attention and Performance (pp. 653–675). Cambridge, MA: MIT Press.</ref> but so far it is not clear whether the decline in inhibitory ability fully explains the decline of working-memory capacity. An explanation on the neural level of the decline of working memory and other cognitive functions in old age has been proposed by West.<ref>{{cite journal | doi = 10.1037/0033-2909.120.2.272 | last1 = West | first1 = R. L. | year = 1996 | title = An application of prefrontal cortex function theory to cognitive aging | url = | journal = Psychological Bulletin | volume = 120 | issue = 2| pages = 272–292 | pmid = 8831298 }}</ref> He argued that working memory depends to a large degree on the [[pre-frontal cortex]], which deteriorates more than other brain regions as we grow old.

==Training==
{{Main|working memory training}}

One theory of [[ADHD|attention-deficit hyperactivity disorder]] states that ADHD can lead to deficits in working memory.<ref>Barkley: ''Attention-Deficit Hyperactivity Disorder,'' third edition 2006{{Page needed|date=September 2010}}</ref> Studies suggest that working memory can be improved by training in ADHD patients through computerized programs.<ref>{{Cite journal|author=Klingberg T, Forssberg H, Westerberg H |title=Training of working memory in children with ADHD |journal=Journal of Clinical and Experimental Neuropsychology |volume=24 |issue=6 |pages=781–91 |year=2002 |month=September |pmid=12424652 |doi=10.1076/jcen.24.6.781.8395}}</ref> This random controlled study has found that a period of [[working memory training]] increases a range of cognitive abilities and increases IQ test scores. Consequently, this study supports previous findings suggesting that working memory underlies general intelligence. Another study of the same group<ref>{{Cite journal|author=Olesen PJ, Westerberg H, Klingberg T |title=Increased prefrontal and parietal activity after training of working memory |journal=Nature Neuroscience |volume=7 |issue=1 |pages=75–9 |year=2004 |month=January |pmid=14699419 |doi=10.1038/nn1165}}</ref> has shown that, after training, measured brain activity related to working memory increased in the prefrontal cortex, an area that many researchers have associated with working memory functions. It has been shown that working memory training leads to measurable density changes for cortical [[dopamine]] [[neuroreceptor]]s in test persons.<ref>{{Cite journal|author=McNab F, Varrone A, Farde L, ''et al.'' |title=Changes in cortical dopamine D1 receptor binding associated with cognitive training |journal=Science |volume=323 |issue=5915 |pages=800–2 |year=2009 |month=February |pmid=19197069 |doi=10.1126/science.1166102}}</ref>

A controversial study has shown that training with a working memory task (the dual [[n-back]] task) improves performance on a very specific fluid [[intelligence test]] in healthy young adults.<ref>{{Cite journal|author=Jaeggi SM, Buschkuehl M, Jonides J, Perrig WJ |title=Improving fluid intelligence with training on working memory |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=105 |issue=19 |pages=6829–33 |year=2008 |month=May |pmid=18443283 |pmc=2383929 |doi=10.1073/pnas.0801268105}}</ref> The study's conclusion that improving or augmenting the brain's working memory ability increases [[fluid intelligence]] is backed by some<ref>{{Cite journal|author=Sternberg RJ |title=Increasing fluid intelligence is possible after all |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=105 |issue=19 |pages=6791–2 |year=2008 |month=May |pmid=18474863 |pmc=2383939 |doi=10.1073/pnas.0803396105}}</ref>
and questioned by others.<ref>{{Cite journal|doi=10.1016/j.intell.2009.04.005 |title=Can intelligence be increased by training on a task of working memory? |year=2009 |last1=Moody |first1=David E. |journal=Intelligence |volume=37 |issue=4 |pages=327–8}}</ref> The study was replicated in 2010.<ref>Jaeggi, S. M., Studer-Luethi, B., Buschkuehl, M., Su, Y.-F., Jonides, J., & Perrig, W. (in press). The relationship between n-back performance and matrix reasoning - implications for training and transfer. Intelligence.</ref>

In Torkel Klingberg's 2009 book ''The Overflowing Brain'',<ref>{{Cite book|author=T. Klingberg |title=The overflowing brain: information overload and the limits of working memory |publisher=Oxford University Press |isbn=978-0-19-537288-5 |year=2009}}</ref> he proposes that working memory is enhanced through exposure to excess neural activation. The [[brain mapping|brain map]] of an individual, he argues, can be altered by this activation to create a larger area of the brain activated by a particular type of sensory experience. An example would be that in learning to play guitar, the area activated by sensory impressions of the instrument is larger in the brain of a player than it is in a nonplayer.

There is evidence that optimal working memory performance links to the neural ability to focus attention on task-relevant information and ignore distractions,<ref>{{Cite journal|author=Zanto TP, Gazzaley A |title=Neural suppression of irrelevant information underlies optimal working memory performance |journal=The Journal of Neuroscience |volume=29 |issue=10 |pages=3059–66 |year=2009 |month=March |pmid=19279242 |pmc=2704557 |doi=10.1523/JNEUROSCI.4621-08.2009}}</ref> and that practice-related improvement in working memory is due to increasing these abilities.<ref>{{cite journal | doi = 10.1152/jn.00179.2009 | last1 = Berry | first1 = A.S. | last2 = Zanto | first2 = T.P. | last3 = Rutman | first3 = A.M. | last4 = Clapp | first4 = W.C. | last5 = Gazzaley | first5 = A. | year = 2009 | title = Practice-related improvement in working memory is modulated by changes in processing external interference | url = | journal = Journal of Neurophysiology | volume = 102 | issue = 3| pages = 1779–89 | pmid = 19587320 | pmc = 2746773 }}</ref>

Working memory performance may also be increased by high intensity exercise. A study was conducted with both sedentary and active females 18–25 years old in which the effects of short-term exercise to exhaustion on working memory was measured. While the working memory of the subjects decreased during and immediately after the exercise bouts, it was shown that the subjects' working memory had an increase following recovery.<ref>{{cite journal|journal=Perceptual & Motor Skills|volume=107 |issue=3 |pages=933–945|year=2008 |month=December |pmid=19235422 |doi=10.2466/PMS.107.3.933-945}}</ref>

However a recent review paper has called into question much of the "success" of working memory training studies.<ref>{{Cite journal|author=Shipstead Z, Redick TS, Engle RW |title=Does working memory training generalize? |journal=Psychologica Belgica |volume=50 |issue=3&4 |pages=245–276 |year=2010}}</ref> Shipstead et al. (2010) point out that working memory training studies are plagued with poor experimental design. The majority of training studies utilize a no-contact control group making it impossible to determine whether any benefit of training is due to actual improvement or a [[Hawthorne effect]].

==Working memory in the brain==
===Genetics ===
Little is known of the genetics of working memory. It is [[heritable]],<ref>{{Cite journal|author=Sherry, D. F., and Schacter, D. L. |title=The evolution of multiple memory systems |journal=Psychological Review |volume=94 |pages=439–454 |year=1987}}</ref> and, at a component level, one candidate gene has been proposed, namely [[ROBO1]] for the [[phonological loop]] function of working memory.

===Physiology and Psychopharmacology===
The first insights into the neuronal and neurotransmitter basis of working memory came from animal research. The work of Jacobsen<ref>{{Cite journal|author=Jacobsen CF|title= Studies of cerebral function in primates |journal=Comp Psychol Monogr |volume=13 |pages=1–68 |year=1938}}</ref> and Fulton in the 1930s first showed that lesions to the PFC impaired spatial working memory performance in monkeys. The later work of Fuster<ref>{{Cite journal|author=Fuster JM |title=Unit activity in prefrontal cortex during delayed-response performance: neuronal correlates of transient memory |journal=Journal of Neurophysiology |volume=36 |issue=1 |pages=61–78 |year=1973 |month=January |pmid=4196203 |url=http://jn.physiology.org/cgi/pmidlookup?view=long&pmid=4196203}}</ref> recorded the electrical activity of neurons in the PFC of monkeys while they were doing a delayed matching task. In that task, the monkey sees how the experimenter places a bit of food under one of two identical looking cups. A shutter is then lowered for a variable delay period, screening off the cups from the monkey's view. After the delay, the shutter opens and the monkey is allowed to retrieve the food from under the cups. Successful retrieval in the first attempt – something the animal can achieve after some training on the task – requires holding the location of the food in memory over the delay period. Fuster found neurons in the PFC that fired mostly during the delay period, suggesting that they were involved in representing the food location while it was invisible. Later research has shown similar delay-active neurons also in the posterior [[parietal cortex]], the [[thalamus]], the [[Caudate nucleus|caudate]], and the [[globus pallidus]].<ref>{{Cite journal|author=Ashby FG, Ell SW, Valentin VV, Casale MB |title=FROST: a distributed neurocomputational model of working memory maintenance |journal=Journal of Cognitive Neuroscience |volume=17 |issue=11 |pages=1728–43 |year=2005 |month=November |pmid=16269109 |doi=10.1162/089892905774589271}}</ref> The work of [[Patricia Goldman-Rakic|Goldman-Rakic]] and others showed that principal sulcal, dorsolateral PFC interconnects with all of these brain regions, and that neuronal microcircuits within PFC are able to maintain information in working memory through recurrent excitatory glutamate networks of pyramidal cells that continue to fire throughout the delay period.<ref>{{Cite journal|author=Goldman-Rakic PS|title= Cellular basis of working memory |journal=Neuron |volume=14 |pages=447–485 |year=1995}}</ref> These circuits are tuned by lateral inhibition from GABAergic interneurons.<ref>{{Cite journal|author=Rao SG, Williams GV, Goldman-Rakic PS|title= Destruction and creation of spatial tuning by disinhibition: GABA(A) blockade of prefrontal cortical neurons engaged by working memory |journal=J. Neuroscience |volume=20 |pages=485–494 |year=2000}}</ref> The neuromodulatory arousal systems markedly alter PFC working memory function; for example, either too little or too much dopamine or norepinephrine impairs PFC network firing <ref>{{Cite journal|doi=10.1016/j.tics.2010.05.003|author=Arnsten AFT, Paspalas CD, Gamo NJ, Y. Y, Wang M|title= Dynamic Network Connectivity: A new form of neuroplasticity|journal=Trends Cognitive Sci.|volume=14 |pages=365–375 |year=2010|issue=8|pmid=20554470|pmc=2914830}}</ref> and working memory performance.<ref>{{Cite journal|doi=10.1146/annurev.neuro.051508.135535|author=Robbins TW, Arnsten AF|title= The neuropsychopharmacology of fronto-executive function: monoaminergic modulation |journal=Annu Rev Neurosci|volume=32 |pages=267–287 |year=2009|pmid=19555290|pmc=2863127}}</ref>

===Localization===
Localization of brain functions in humans has become much easier with the advent of [[brain imaging]] methods ([[Positron emission tomography|PET]] and [[fMRI]]). This research has confirmed that areas in the PFC are involved in working memory functions. During the 1990s much debate has centered on the different functions of the ventrolateral (i.e., lower areas) and the [[Dorsolateral prefrontal cortex|dorsolateral (higher) areas of the PFC]]. One view was that the dorsolateral areas are responsible for spatial working memory and the ventrolateral areas for non-spatial working memory. Another view proposed a functional distinction, arguing that ventrolateral areas are mostly involved in pure maintenance of information, whereas dorsolateral areas are more involved in tasks requiring some processing of the memorized material. The debate is not entirely resolved but most of the evidence supports the functional distinction.<ref>{{Cite journal|author=Owen AM |title=The functional organization of working memory processes within human lateral frontal cortex: the contribution of functional neuroimaging |journal=The European Journal of Neuroscience |volume=9 |issue=7 |pages=1329–39 |year=1997 |month=July |pmid=9240390 |doi=10.1111/j.1460-9568.1997.tb01487.x}}</ref>

Brain imaging has also revealed that working memory functions are by far not limited to the PFC. A review of numerous studies<ref>{{Cite journal|author=Smith EE, Jonides J |title=Storage and executive processes in the frontal lobes |journal=Science |volume=283 |issue=5408 |pages=1657–61 |year=1999 |month=March |pmid=10073923 |doi=10.1126/science.283.5408.1657}}</ref> shows areas of activation during working memory tasks scattered over a large part of the cortex. There is a tendency for spatial tasks to recruit more right-hemisphere areas, and for verbal and object working memory to recruit more left-hemisphere areas. The activation during verbal working memory tasks can be broken down into one component reflecting maintenance, in the left posterior parietal cortex, and a component reflecting subvocal rehearsal, in the left frontal cortex (Broca's area, known to be involved in speech production).<ref>{{Cite journal|author=Smith EE, Jonides J, Marshuetz C, Koeppe RA |title=Components of verbal working memory: evidence from neuroimaging |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=95 |issue=3 |pages=876–82 |year=1998 |month=February |pmid=9448254 |pmc=33811 |doi=10.1073/pnas.95.3.876}}</ref>

There is an emerging consensus that most working memory tasks recruit a network of PFC and parietal areas. A study has shown that during a working memory task the connectivity between these areas increases.<ref>{{Cite journal|author=Honey GD, Fu CH, Kim J, ''et al.'' |title=Effects of verbal working memory load on corticocortical connectivity modeled by path analysis of functional magnetic resonance imaging data |journal=NeuroImage |volume=17 |issue=2 |pages=573–82 |year=2002 |month=October |pmid=12377135 |doi=10.1016/S1053-8119(02)91193-6}}</ref> Another study has demonstrated that these areas are necessary for working memory, and not simply activated accidentally during working memory tasks, by temporarily blocking them through [[transcranial magnetic stimulation]] (TMS), thereby producing an impairment in task performance.<ref>{{Cite journal|author=Mottaghy FM |title=Interfering with working memory in humans |journal=Neuroscience |volume=139 |issue=1 |pages=85–90 |year=2006 |month=April |pmid=16337091 |doi=10.1016/j.neuroscience.2005.05.037}}</ref>

A current debate concerns the function of these brain areas. The PFC has been found to be active in a variety of tasks that require executive functions.<ref name="Kane MJ, Engle RW 2002 637–71"/> This has led some researchers to argue that the role of PFC in working memory is in controlling attention, selecting strategies, and manipulating information in working memory, but not in maintenance of information. The maintenance function is attributed to more posterior areas of the brain, including the parietal cortex.<ref>{{Cite journal|author=Curtis CE, D'Esposito M |title=Persistent activity in the prefrontal cortex during working memory |journal=Trends in Cognitive Sciences |volume=7 |issue=9 |pages=415–423 |year=2003 |month=September |pmid=12963473 |doi=10.1016/S1364-6613(03)00197-9}}</ref><ref name= 'Postle'>{{Cite journal|author=Postle BR |title=Working memory as an emergent property of the mind and brain |journal=Neuroscience |volume=139 |issue=1 |pages=23–38 |year=2006 |month=April |pmid=16324795 |pmc=1428794 |doi=10.1016/j.neuroscience.2005.06.005}}</ref> Other authors interpret the activity in parietal cortex as reflecting [[executive functions]], because the same area is also activated in other tasks requiring executive attention but no memory<ref>{{Cite journal|author=Collette F, Hogge M, Salmon E, Van der Linden M |title=Exploration of the neural substrates of executive functioning by functional neuroimaging |journal=Neuroscience |volume=139 |issue=1 |pages=209–21 |year=2006 |month=April |pmid=16324796 |doi=10.1016/j.neuroscience.2005.05.035}}</ref>

Working memory has been suggested to involve two processes with different neuroanatomical locations in the frontal and parietal lobes.<ref name="Bledowski">{{Cite journal|author=Bledowski C, Rahm B, Rowe JB |title=What 'works' in working memory? Separate systems for selection and updating of critical information |journal=The Journal of Neuroscience |volume=29 |issue=43 |pages=13735–41 |year=2009 |month=October |pmid=19864586 |doi=10.1523/JNEUROSCI.2547-09.2009 |pmc=2785708}}</ref> First, a selection operation that retrieves the most relevant item, and second an updating operation that changes the focus of attention made upon it. Updating the attentional focus has been found to involve the transient activation in the caudal [[superior frontal sulcus]] and [[posterior parietal cortex]]. While increasing demands on selection selectively changes activation in the rostral superior frontal sulcus and posterior cingulate/[[precuneus]].<ref name="Bledowski"/>

Articulating the differential function of brain regions involved in working memory is dependent on task able to distinguish these functions.<ref>M. Coltheart. (2006). What has functional neuroimaging told us about the mind (so far)? ''Cortex; a journal devoted to the study of the nervous system and behavior'', '''42''', [http://dx.doi.org/323-31]</ref> Most brain imaging studies of working memory have used recognition tasks such as delayed recognition of one or several stimuli, or the n-back task, in which each new stimulus in a long series must be compared to the one presented n steps back in the series. The advantage of recognition tasks is that they require minimal movement (just pressing one of two keys), making fixation of the head in the scanner easier. Experimental research and research on individual differences in working memory, however, has used largely recall tasks (e.g., the [[reading span task]], see below). It is not clear to what degree recognition and recall tasks reflect the same processes and the same capacity limitations.

A few brain imaging studies have been conducted with the reading span task or related tasks. Increased activation during these tasks was found in the PFC and, in several studies, also in the [[anterior cingulate cortex]] (ACC). People performing better on the task showed larger increase of activation in these areas, and their activation was correlated more over time, suggesting that their neural activity in these two areas was better coordinated, possibly due to stronger connectivity.<ref>{{Cite journal|author=Kondo H, Osaka N, Osaka M |title=Cooperation of the anterior cingulate cortex and dorsolateral prefrontal cortex for attention shifting |journal=NeuroImage |volume=23 |issue=2 |pages=670–9 |year=2004 |month=October |pmid=15488417 |doi=10.1016/j.neuroimage.2004.06.014}}</ref><ref>{{Cite journal|author=Osaka N, Osaka M, Kondo H, Morishita M, Fukuyama H, Shibasaki H |title=The neural basis of executive function in working memory: an fMRI study based on individual differences |journal=NeuroImage |volume=21 |issue=2 |pages=623–31 |year=2004 |month=February |pmid=14980565 |doi=10.1016/j.neuroimage.2003.09.069}}</ref>

===Effects of stress===
Working memory is impaired by acute and chronic psychological stress. This phenomenon was first discovered in animal studies by Arnsten and colleagues,<ref>{{Cite journal|doi=10.1126/science.280.5370.1711|author=Arnsten, AF |title=The biology of being frazzled |journal=Science |volume=280 |issue=5370 |pages=1711–2 |year=1998 |month=June |pmid=9660710}}</ref> who have shown that stress-induced catecholamine release in PFC rapidly decreases PFC neuronal firing and impairs working memory performance through feedforward, intracellular signaling pathways.<ref>{{Cite journal|author=Arnsten, AF |title=Stress signalling pathways that impair prefrontal cortex structure and function |journal=Nat Rev Neurosci. |volume=10 |issue=6 |pages=410–22 |year=2009 |month=June |pmid=19455173|pmc=2907136 |doi=10.1038/nrn2648}}</ref> Exposure to chronic stress leads to more profound working memory deficits and additional architectural changes in PFC, including dendritic atrophy and spine loss,<ref>{{Cite journal|author=Radley JJ, Rocher AB, Miller M, Janssen WG, Liston C, Hof PR, McEwen BS, Morrison JH |title=Repeated stress induces dendritic spine loss in the rat medial prefrontal cortex |journal=Cereb Cortex |volume=16 |issue=3 |pages=313–20 |year=2006 |month=Mar |pmid=15901656 |doi=10.1093/cercor/bhi104}}</ref> which can be prevented by inhibition of protein kinase C signaling.<ref>{{Cite journal|author=Hains AB, Vu MA, Maciejewski PK, van Dyck CH, Gottron M, Arnsten AF. |title=Inhibition of protein kinase C signaling protects prefrontal cortex dendritic spines and cognition from the effects of chronic stress |journal=Proc Natl Acad Sci U S A. |volume=106 |issue=42 |pages=17957–62 |year=2009 |month=Oct |pmid=19805148|pmc=2742406 |doi=10.1073/pnas.0908563106}}</ref> [[fMRI]] research has extended this research to humans, and confirms that reduced working memory caused by acute stress links to reduced activation of the PFC, and stress increased levels of [[catecholamine]]s.<ref>{{Cite journal|author=Qin S, Hermans EJ, van Marle HJ, Luo J, Fernández G |title=Acute psychological stress reduces working memory-related activity in the dorsolateral prefrontal cortex |journal=Biological Psychiatry |volume=66 |issue=1 |pages=25–32 |year=2009 |month=July |pmid=19403118 |doi=10.1016/j.biopsych.2009.03.006}}</ref> Imaging studies of medical students undergoing stressful exams have also shown weakened PFC functional connectivity, consistent with the animal studies.<ref>{{Cite journal|author=Liston C, McEwen BS, Casey BJ |title=Psychosocial stress reversibly disrupts prefrontal processing and attentional control |journal=Proc Natl Acad Sci U S A |volume=106 |issue=3 |pages=912–7 |year=2009 |month=Jan |pmid=19139412|pmc=2621252 |doi=10.1073/pnas.0807041106}}</ref> The marked effects of stress on PFC structure and function may help to explain how stress can cause or exacerbate mental illness.

==Neural maintenance==
Much has been learned over the last two decades on where in the brain working memory functions are carried out. Much less is known on how the brain accomplishes short-term maintenance and goal-directed manipulation of information. The persistent firing of certain neurons in the delay period of working memory tasks shows that the brain has a mechanism of keeping representations active without external input.

Keeping representations active, however, is not enough if the task demands maintaining more than one chunk of information. In addition, the components and features of each chunk must be bound together to prevent them from being mixed up. For example, if a red triangle and a green square must be remembered at the same time, one must make sure that "red" is bound to "triangle" and "green" is bound to "square". One way of establishing such bindings is by having the neurons that represent features of the same chunk fire in synchrony, and those that represent features belonging to different chunks fire out of sync.<ref>{{Cite journal|author=Raffone A, Wolters G |title=A cortical mechanism for binding in visual working memory |journal=Journal of Cognitive Neuroscience |volume=13 |issue=6 |pages=766–85 |year=2001 |month=August |pmid=11564321 |doi=10.1162/08989290152541430}}</ref> In the example, neurons representing redness would fire in synchrony with neurons representing the triangular shape, but out of sync with those representing the square shape. So far, there is no direct evidence that working memory uses this binding mechanism, and other mechanisms have been proposed as well.<ref>{{Cite book|first1=Randall C. |last1=O'Reilly |first2=Richard S. |last2=Busby |first3=Rodolfo |last3=Soto |year=2003 |chapter=Three forms of binding and their neural substrates: Alternatives to temporal synchrony |editor1-first=Axel |editor1-last=Cleeremans |title=The unity of consciousness: Binding, integration, and dissociation |pages=168–90 |chapterurl=http://psycnet.apa.org/psycinfo/2003-88180-008 |isbn=978-0-19-850857-1 |oclc=50747505 |author=edited by Axel Cleeremans. |publisher=Oxford University Press |location=Oxford}}</ref> It has been speculated that synchronous firing of neurons involved in working memory oscillate with frequencies in the [[theta rhythm|theta]] band (4 to 8 Hz). Indeed, the power of theta frequency in the EEG increases with working memory load,<ref>{{Cite book|last1=Klimesch |first1=W. |year=2006 |chapter=Binding principles in the theta frequency range |editor1-first=H. D. |editor1-last=Zimmer |editor2-first=A. |editor2-last=Mecklinger |editor3-first=U. |editor3-last=Lindenberger |title=Handbook of binding and memory |pages=115–144 |location=Oxford |publisher=Oxford University Press}}</ref> and oscillations in the theta band measured over different parts of the skull become more coordinated when the person tries to remember the binding between two components of information.<ref>{{Cite journal|author=Wu X, Chen X, Li Z, Han S, Zhang D |title=Binding of verbal and spatial information in human working memory involves large-scale neural synchronization at theta frequency |journal=NeuroImage |volume=35 |issue=4 |pages=1654–62 |year=2007 |month=May |pmid=17379539 |doi=10.1016/j.neuroimage.2007.02.011}}</ref>

One modern approach to explain the working memory in the brain is [[PBWM|Prefrontal Cortex Basal Ganglia Working Memory (PBWM)]].

==Learning==
There is now extensive evidence that working memory is linked to key learning outcomes in literacy and numeracy.<ref>Cowan, N., & Alloway, T.P. (2008). The development of working memory. In N. Cowan (Ed). Development of Memory in Childhood, 2nd edition, pp. 303–342. Hove, England: Psychology Press</ref> A longitudinal study confirmed that a child's working memory at 5 years old is a better predictor of academic success than IQ.<ref>{{Cite journal|author=Alloway TP, Alloway RG|title=Investigating the predictive roles of working memory and IQ in academic attainment |journal=Journal of Experimental Child Psychology |volume=80|issue=2|pages= 606–21|year=2010|pmid=20018296 |doi=10.1016/j.jecp.2009.11.003}}</ref>

In a large-scale screening study, one in ten children in mainstream classrooms were identified with working memory deficits. The majority of them performed very poorly in academic achievements, independent of their IQ.<ref>{{Cite journal|author=Alloway TP, Gathercole SE, Kirkwood H, Elliott J |title=The cognitive and behavioral characteristics of children with low working memory |journal=Child Development |volume=80 |issue=2 |pages=606–21 |year=2009 |pmid=19467014 |doi=10.1111/j.1467-8624.2009.01282.x}}</ref> Without appropriate intervention, these children lag behind their peers. A recent study of 37 school-age children with significant learning disabilities has shown that working memory capacity at baseline measurement, but not IQ, predicts learning outcomes two years later.<ref>{{Cite journal|first1=Tracy Packiam |last1=Alloway |year=2009 |journal=European Journal of Psychological Assessment |volume=25 |issue=2 |pages=92–8 |doi=10.1027/1015-5759.25.2.92 |title=Working Memory, but Not IQ, Predicts Subsequent Learning in Children with Learning Difficulties}}</ref> This suggests that working memory impairments are associated with low learning outcomes and constitute a high risk factor for educational underachievement for children. In children with learning disabilities such as [[dyslexia]], [[ADHD]], and developmental coordination disorder, a similar pattern is evident.<ref>{{Cite book|editor1-first=Tracy Packiam |editor1-last=Alloway |editor2-first=Susan E. |year=2006 |title=Working memory and neurodevelopmental disorders |location=[[Hove]] |publisher=Psychology Press |isbn=978-1-84169-560-0 |oclc=254981332 |editor2=lastGathercole |author=edited by Tracy Packiam Alloway and Susan E. Gathercole.}}{{Page needed|date=September 2010}}</ref>

In a classroom, common characteristics of working memory impairment include a failure to remember instructions and an inability to complete learning activities. Without early diagnosis, working memory impairment negatively impacts a child's performance throughout their scholastic career.<ref>{{Cite book
|first1=Susan E. |last1=Gathercole |first2=Tracy Packiam |last2=Alloway |title=Working Memory and Learning: A Practical Guide for Teachers |publisher=SAGE Publications |year=2008 |location=London |url=http://www.sagepub.com/booksProdDesc.nav?prodId=Book230942#tabview=title |isbn=978-1-4129-3613-2 |oclc=228192899
|author=Tracy Packiam Alloway and Susan E. Gathercole.}}</ref>

However, strategies that target the specific strengths and weaknesses of the student's working memory profile are available for educators.<ref>{{Cite book
|first1=Tracy Packiam |last1=Alloway |title=Improving Working Memory: Supporting Students' Learning |publisher=SAGE Publications |year=2010 |location=London |url=http://www.sagepub.com/booksProdDesc.nav?prodId=Book230942#tabview=title |isbn=978-1-8492-0748-5 |author=Tracy Packiam Alloway.}}</ref>

==Attention==
Research suggests a close link between the working memory capacities of a person and their ability to control the information from the environment that they can selectively enhance or ignore.<ref name="attention09">{{Cite journal|author=Fukuda K, Vogel EK |title=Human variation in overriding attentional capture |journal=The Journal of Neuroscience |volume=29 |issue=27 |pages=8726–33 |year=2009 |month=July |pmid=19587279 |doi=10.1523/JNEUROSCI.2145-09.2009}}</ref> Such attention allows for example for the voluntarily shifting in regard to goals of a person's information processing to spatial locations or objects rather than ones that capture their attention due to their sensory [[salience (neuroscience)|saliency]] (such as an ambulance siren). The goal directing of attention is driven by "top-down" signals from the PFC that bias processing in posterior cortical areas<ref>{{Cite journal|author=Desimone R, Duncan J |title=Neural mechanisms of selective visual attention |journal=Annual Review of Neuroscience |volume=18 |issue= |pages=193–222 |year=1995 |pmid=7605061 |doi=10.1146/annurev.ne.18.030195.001205}}</ref> and saliency capture by "bottom-up" control from subcortical structures and the primary sensory cortices.<ref>{{Cite journal|author=Yantis S, Jonides J |title=Abrupt visual onsets and selective attention: voluntary versus automatic allocation |journal=Journal of Experimental Psychology. Human Perception and Performance |volume=16 |issue=1 |pages=121–34 |year=1990 |month=February |pmid=2137514 |url=http://content.apa.org/journals/xhp/16/1/121 |doi=10.1037/0096-1523.16.1.121}}</ref> The ability to override sensory capture of attention differs greatly between individuals and this difference closely links to their working memory capacity. The greater a person's working memory capacity, the greater their ability to resist sensory capture.<ref name="attention09"/> The limited ability to override attentional capture is likely to result in the unnecessary storage of information in working memory,<ref name="attention09"/> suggesting not only that having a poor working memory affects attention but that it can also limit the capacity of working memory even further.

==Research==
Today there are hundreds of research laboratories around the world studying various aspects of working memory. There are numerous applications of working memory in the field, such as using working memory capacity to explain [[intelligence]], success at emotion regulation,<ref>{{Cite journal|author=Schmeichel BJ, Volokhov RN, Demaree HA |title=Working memory capacity and the self-regulation of emotional expression and experience |journal=Journal of Personality and Social Psychology |volume=95 |issue=6 |pages=1526–40 |year=2008 |month=December |pmid=19025300 |doi=10.1037/a0013345}}</ref> and other cognitive abilities,<ref>Conway, A. R. A., Jarrold, C., Kane, M. J., Miyake, A., & Towse, J. N. (Eds.). (2007). Variation in working memory. New York: Oxford University Press{{Page needed|date=September 2010}}</ref> furthering the understanding of [[autism spectrum disorder]]s,<ref>{{Cite journal|author=Kenworthy L, Yerys BE, Anthony LG, Wallace GL |title=Understanding executive control in autism spectrum disorders in the lab and in the real world |journal=Neuropsychology Review |volume=18 |issue=4 |pages=320–38 |year=2008 |month=December |pmid=18956239 |doi=10.1007/s11065-008-9077-7 |pmc=2856078}}</ref> [[attention-deficit hyperactivity disorder|ADHD]],<ref>{{cite journal | doi = 10.2174/1389450013348155 | last1 = Levy | first1 = F. | last2 = Farrow | first2 = M. | year = 2001 | title = Working memory in ADHD: prefrontal/parietal connections | url = | journal = Curr Drug Targets | volume = 2 | issue = 4| pages = 347–352 | pmid = 11732636 }}</ref> [[motor skills disorder|motor dyspraxia]],<ref>{{Cite journal|author=Alloway TP |title=Working memory, reading, and mathematical skills in children with developmental coordination disorder |journal=Journal of Experimental Child Psychology |volume=96 |issue=1 |pages=20–36 |year=2007 |month=January |pmid=17010988 |doi=10.1016/j.jecp.2006.07.002}}</ref> and improving [[teaching methods]],<ref name= 'Postle'/> [[educational attainment]],<ref>{{cite web|title=Investigating the predictive roles of working memory and IQ in academic attainment.|url=http://www.ncbi.nlm.nih.gov/pubmed/20018296}}</ref> and creating [[artificial intelligence]] based on the [[human brain]].<ref>{{Cite journal|author=Constantinidis C, Wang XJ |title=A neural circuit basis for spatial working memory |journal=The Neuroscientist |volume=10 |issue=6 |pages=553–65 |year=2004 |month=December |pmid=15534040 |doi=10.1177/1073858404268742}}</ref><ref>{{Cite journal|author=Vogels TP, Rajan K, Abbott LF |title=Neural network dynamics |journal=Annual Review of Neuroscience |volume=28 |issue= |pages=357–76 |year=2005 |pmid=16022600 |doi=10.1146/annurev.neuro.28.061604.135637}}</ref>

==See also==
* [[Atkinson–Shiffrin memory model]]
* [[Attention versus memory in prefrontal cortex]]
* [[Fuzzy-trace theory]]
* [[Memory and aging]]
* [[PBWM|Prefrontal Cortex Basal Ganglia Working Memory (PBWM)]]

==References==
{{Reflist|2}}

==External links==
A [http://www.workingmemory.lancs.ac.uk working memory web forum] exists for researchers to post reference information for relevant journal articles and to discuss stimuli, test resources, etc.

{{Memory}}
{{Dyslexia}}
{{Use dmy dates|date=April 2011}}

{{DEFAULTSORT:Working Memory}}
[[Category:Memory processes]]
[[Category:Cognitive science]]
[[Category:Creativity]]
[[Category:Problem solving]]
[[Category:Attention-deficit hyperactivity disorder]]
[[Category:Dyslexia]]

[[de:Arbeitsgedächtnis]]
[[es:memoria de trabajo]]
[[fr:Mémoire de travail]]
[[ko:작용기억]]
[[it:Memoria di lavoro]]
[[lv:Darba atmiņa]]
[[hu:Munkamemória]]
[[nl:Werkgeheugen (mens)]]
[[ja:ワーキングメモリ]]
[[ru:Рабочая память]]
[[fi:Työmuisti]]
[[sv:Arbetsminne (psykologi)]]

Prefrontal cortex

2011-09-13T13:09:00Z

PhineasG: /* Executive Functions */

:''"Prefrontal" redirects here. For the skull bone, see [[Prefrontal bone]]. For the [[reptile]] [[Scale (zoology)|scale]]s, see [[Prefrontal scale]].''
{{Infobox Brain|
Name = Prefrontal cortex |
Latin = |
GraySubject = |
GrayPage = |
Image = Gray726-Brodman-prefrontal.svg |
Caption = [[Brodmann areas]] of lateral surface. Per BrainInfo, parts of #8, #9, #10, #11, #44, #45, #46, and #47 are all in the prefrontal region. |
Image2 = |
Caption2 = |
Width = 300 |
IsPartOf = [[Frontal lobe]]|
Components = [[Superior frontal gyrus]] [[Middle frontal gyrus]] [[Inferior frontal gyrus]]|
Artery = [[Anterior cerebral artery|Anterior cerebral]] [[Middle cerebral artery|Middle cerebral]]|
Vein = [[Superior sagittal sinus]]|
BrainInfoType = ancil |
BrainInfoNumber = 101 |
MeshName = Prefrontal+Cortex |
MeshNumber = A08.186.211.730.885.213.270.700 |
}}
The '''prefrontal cortex''' (PFC) is the [[anterior]] part of the [[frontal lobes]] of the [[brain]], lying in front of the [[primary motor cortex|motor]] and [[premotor cortex|premotor]] areas.

This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior.<ref name="pmid19833485">{{cite journal |author=Yang Y, Raine A |title=Prefrontal structural and functional brain imaging findings in antisocial, violent, and psychopathic individuals: a meta-analysis |journal=Psychiatry Res |volume=174 |issue=2 |pages=81–8 |year=2009 |month=November |pmid=19833485 |pmc=2784035 |doi=10.1016/j.pscychresns.2009.03.012 |url=}}</ref> The basic activity of this brain region is considered to be orchestration of thoughts and actions in accordance with internal goals.<ref name="pmid12217179">{{cite journal |author=Miller EK, Freedman DJ, Wallis JD |title=The prefrontal cortex: categories, concepts and cognition |journal=Philos. Trans. R. Soc. Lond., B, Biol. Sci. |volume=357 |issue=1424 |pages=1123–36 |year=2002 |month=August |pmid=12217179 |pmc=1693009 |doi=10.1098/rstb.2002.1099 |url=}}</ref>

The most typical [[psychology|psychological]] term for functions carried out by the prefrontal cortex area is [[executive system|executive function]]. Executive function relates to abilities to differentiate among conflicting thoughts, determine good and bad, better and best, same and different, future consequences of current activities, working toward a defined goal, prediction of outcomes, expectation based on actions, and social "control" (the ability to suppress urges that, if not suppressed, could lead to socially-unacceptable outcomes).

Many authors have indicated an integral link between a person's personality and the functions of the prefrontal cortex.<ref>{{cite journal | author = DeYoung C. G., Hirsh J. B., Shane M. S., Papademetris X., Rajeevan N., Gray J. R. | year = 2010 | title = Testing predictions from personality neuroscience | url = | journal = Psychological Science | pmid = 20435951 | volume = 21 | issue = 6 | pmc = 3049165| pages = 820–828 | doi = 10.1177/0956797610370159 }}</ref>

==Definition==

There are three possible ways to define the prefrontal cortex:
* as the granular frontal cortex
* as the projection zone of the mediodorsal nucleus of the thalamus
* as that part of the frontal cortex whose electrical stimulation does not evoke movements

The prefrontal cortex has been defined based on [[cytoarchitectonics]] by the presence of a [[Cerebral cortex|cortical granular layer IV]]. It is not entirely clear who first used this criterion. Many of the early cytoarchitectonic researchers restricted the use of the term prefrontal to a much smaller region of cortex including the [[gyrus rectus]] and the [[gyrus]] [[rostralis]] ([[Alfred Walter Campbell|Campbell]], 1905; [[Grafton Elliot Smith|G. E. Smith]], 1907; [[Korbinian Brodmann|Brodmann]], 1909; [[Constantin von Economo|von Economo]] and [[Georg N. Koskinas|Koskinas]], 1925). In 1935, however, [[Carlyle F. Jacobsen|Jacobsen]] used the term prefrontal to distinguish granular prefrontal areas from agranular motor and premotor areas.<ref name="isbn0-19-514694-8">{{cite book |author=Finger, Stanley |title=Origins of neuroscience: a history of explorations into brain function |publisher=Oxford University Press |location=Oxford [Oxfordshire] |year=1994 |pages= |isbn=0-19-514694-8 |oclc= |doi= |accessdate=}}</ref> In terms of Brodmann areas, the prefrontal cortex traditionally includes areas 8, 9, 10, 11, 44, 45, 46, and 47 (to complicate matters, not all of these areas are strictly granular—44 is dysgranular, caudal 11 and orbital 47 are agranular<ref name="preuss95">{{cite journal |author=Preuss TM |title=Do rats have prefrontal cortex? The Rose-Woolsey-Akert program reconsidered. |journal=The Journal of Cogntive Neuroscience |volume=7 |issue=1 |pages=1–24 |year=1995 |doi=10.1162/jocn.1995.7.1.1 }}</ref>). The main problem with this definition is that it works well only in primates but not in nonprimates, as the latter lack a granular layer IV.<ref name="pmid14643455">{{cite journal |author=Uylings HB, Groenewegen HJ, Kolb B |title=Do rats have a prefrontal cortex? |journal=Behavioural Brain Research |volume=146 |issue=1–2 |pages=3–17 |year=2003 |month=November |pmid=14643455 |doi= 10.1016/j.bbr.2003.09.028|url=http://linkinghub.elsevier.com/retrieve/pii/S0166432803003346}}</ref>

To define the prefrontal cortex as the projection zone of the [[Medial dorsal nucleus|mediodorsal nucleus]] of the [[thalamus]] builds on the work of Rose and Woolsey<ref name="pmid18106857">{{cite journal |author=Rose JE, Woolsey CN |title=The orbitofrontal cortex and its connections with the mediodorsal nucleus in rabbit, sheep and cat |journal=Research Publications - Association for Research in Nervous and Mental Disease |volume=27 (1 vol.) |issue= |pages=210–32 |year=1948 |pmid=18106857 |doi= |url=}}</ref> who showed that this nucleus projects to anterior and ventral parts of the brain in nonprimates. Rose and Woolsey however termed this projection zone "orbitofrontal." It seems to have been Akert, who in 1964 for the first time explicitly suggested that this criterion could be used to define homologues of the prefrontal cortex in primates and nonprimates.<ref name="pmid1939732">{{cite journal |author=Preuss TM, Goldman-Rakic PS |title=Myelo- and cytoarchitecture of the granular frontal cortex and surrounding regions in the strepsirhine primate Galago and the anthropoid primate Macaca |journal=The Journal of Comparative Neurology |volume=310 |issue=4 |pages=429–74 |year=1991 |month=August |pmid=1939732 |doi=10.1002/cne.903100402 |url=}}</ref> This allowed the establishment of homologies despite the lack of a granular frontal cortex in nonprimates.
The projection zone definition is still widely accepted today (e.g. [[Joaquin Fuster|Fuster]]<ref name="isbn0-12-373644-7">{{cite book |author=Fuster, Joaquin M. |title=The Prefrontal Cortex, Fourth Edition |publisher=Academic Press |location=Boston |year=2008 |pages= |isbn=0-12-373644-7 |oclc= |doi= |accessdate=}}</ref>), although its usefulness has been questioned.<ref name="preuss95" /><ref name="marko79">{{cite journal |author=Markowitsch HJ, Pritzel, M |title=The prefrontal cortex: Projection area of the thalamic mediodorsal nucleus? |journal=Physiological Psychology |volume=7 |issue=1 |pages=1–6 |year=1979 | url=http://psycnet.apa.org/psycinfo/1980-29827-001 | accessdate=2 April 2011 }}</ref> Modern tract tracing studies have shown that projections of the mediodorsal nucleus of the thalamus are not restricted to the granular frontal cortex in primates. As a result, it was suggested to define the prefrontal cortex as the region of cortex which has stronger reciprocal connections with the mediodorsal nucleus than with any other thalamic nucleus.<ref name="pmid14643455" /> Uylings et al.<ref name="pmid14643455" /> acknowledge, however, that even with the application of this criterion it might be rather difficult to unequivocally define the prefrontal cortex.

A third definition of the prefrontal cortex is the area of frontal cortex whose electrical stimulation does not lead to observable movements. For example, in 1890 [[David Ferrier]]<ref name="ferrier90">{{cite journal |author=Ferrier D |title=The Croonian lectures on cerebral localisation. Lecture II |journal=The British Medical Journal |volume=1 |issue=1537 |pages=1349–1355 |year=1890 |doi=10.1136/bmj.1.1537.1349 |pmc=2207859 |pmid=20753055}}</ref> used the term in this sense. One complication with this definition is that the electrically "silent" frontal cortex includes both granular and non-granular areas.<ref name="preuss95" />

==Etymology==

The term "prefrontal" as describing a part of the brain appears to have been introduced by Richard Owen in 1868.<ref name="isbn0-19-514694-8" /> For him, the prefrontal area was restricted to the anterior-most part of the frontal lobe (approximately corresponding to the frontal pole). It has been hypothesized that his choice of the term was based on the [[prefrontal bone]] present in most amphibians and reptiles.<ref name="isbn0-19-514694-8" />

==Subdivisions==

The table below shows different ways to subdivide the prefrontal cortex starting from Brodmann areas. Note that the term "dorsolateral" has been used to denote areas 8, 9, and 46 as well as areas 8, 9, 44, 45, 46, and lateral 47{{Citation needed|date=May 2010}} and several terms are given to areas 47, 11 and 10.

{| class="wikitable"
!width="60" | <center>8</center>
!width="60" | <center>9</center>
!width="60" | <center>46</center>
!width="60" | <center>44</center>
!width="60" | <center>45</center>
!width="60" | <center>lateral 47</center>
!width="60" | <center>orbital 47</center>
!width="60" | <center>11</center>
!width="60" | <center>10</center>
|-
| colspan="6" | <center>dorsolateral</center>
| colspan="2" rowspan="3" align="center" | <center>[[orbitofrontal cortex|orbitofrontal]], [[Ventromedial prefrontal cortex|ventromedial]], basal, orbital</center>
| rowspan="3" align="center" | <center>frontopolar, anterior, rostral</center>
|-
| colspan="3" | <center>dorsolateral</center>
| colspan="3" rowspan="2"| <center>ventrolateral</center>
|-
| <center>posterior dorsolateral</center>
| colspan="2" | <center>mid-dorsolateral</center>
|}

==Interconnections==

The prefrontal cortex is highly interconnected with much of the brain, including extensive connections with other cortical regions, as well as subcortical areas. The dorsal prefrontal cortex is especially interconnected with brain regions involved with attention, cognition and action,<ref>{{cite journal | doi = 10.1146/annurev.ne.11.030188.001033 | author = Goldman-Rakic PS | year = 1988 | title = Topography of cognition: parallel distributed networks in primate association cortex | url = | journal = Annu Rev Neurosci | volume = 11 | issue = | pages = 137–56 | pmid = 3284439 }}</ref> while the ventral prefrontal cortex interconnects with brain regions involved with emotion.<ref>{{cite journal | doi = 10.1111/j.1749-6632.1999.tb09278.x | author = Price JL | year = 1999 | month = Jun | title = Prefrontal cortical networks related to visceral function and mood | url = | journal = Ann N Y Acad Sci. | volume = 877 | issue = | pages = 383–96 | pmid = 10415660 }}</ref> The prefrontal cortex also receives inputs from the brainstem arousal systems, and its function is particularly dependent on its neurochemical environment.<ref>{{cite journal | doi = 10.1146/annurev.neuro.051508.135535 | author = Robbins TW, Arnsten AF | year = 2009 | title = The neuropsychopharmacology of fronto-executive function: monoaminergic modulation | url = | journal = Annu Rev Neurosci | volume = 32 | issue = | pages = 267–87 | pmid = 19555290 | pmc = 2863127 }}</ref> Thus, there is coordination between our state of arousal and our mental state.<ref>{{cite journal | doi = 10.1016/j.tics.2010.05.003 | author = Arnsten AF, Paspalas CD, Gamo NJ, Yang Y, Wang M | year = 2010 | month = Aug | title = Dynamic Network Connectivity: A new form of neuroplasticity | url = | journal = Trends Cogn Sci. | volume = 14 | issue = 8| pages = 365–75 | pmid = 20554470 | pmc = 2914830 }}</ref>

==Studies==

Perhaps the seminal case in prefrontal cortex function is that of [[Phineas Gage]], one or both of whose frontal lobes was destroyed when a large iron rod was driven through his head in an 1848 accident. The standard presentation (e.g.<ref>[[Antonio Damasio]], ''[[Descartes' Error]]''. [[Penguin Putman Pub.]], 1994</ref>) is that although Gage retained normal memory, speech and motor skills, his personality changed radically: he became irritable, quick-tempered, and impatient—characteristics he did not previously display — so that friends described him as "no longer Gage"; and whereas he had previously been a capable and efficient worker, afterwards he was unable to complete tasks. However, careful analysis of primary evidence shows that descriptions of Gage's psychological changes are usually exaggerated when held against the description given by Gage's doctor, the most striking feature being that changes described years after Gage's death are far more dramatic than anything reported while he was alive.<ref>Malcolm Macmillan, ''An Odd Kind of Fame: Stories of Phineas Gage'' (MIT Press, 2000), pp.116-119, 307-333, esp. pp.11,333.</ref><ref>{{cite journal|author=Macmillan, M. |year=2008|url=http://www.thepsychologist.org.uk/archive/archive_home.cfm/volumeID_21-editionID_164-ArticleID_1399-getfile_getPDF/thepsychologist%5C0908look.pdf|format=PDF|title=Phineas Gage – Unravelling the myth |journal = The Psychologist |publisher=[[British Psychological Society]] | volume= 21 |issue=9 |pages= 828–831 }}</ref>

Subsequent studies, on patients with prefrontal injuries, have shown that the patients verbalized what the most appropriate social responses would be under certain circumstances, yet, when actually performing, they instead pursued behavior that is aimed at immediate gratification despite knowing the longer-term results would be self-defeating.

The interpretation of this data indicates that not only are skills of comparison and understanding of eventual outcomes harbored in the prefrontal cortex but the prefrontal cortex (when functioning correctly) controls the mental option to delay immediate gratification for a better or more rewarding longer-term gratification result. This ability to wait for a reward is one of the key pieces that define optimal executive function of the human brain.

There is much current research devoted to understanding the role of the prefrontal cortex in neurological disorders. Many disorders, such as [[schizophrenia]], [[bipolar disorder]] and [[ADHD]], have been related to dysfunction of the prefrontal cortex, and thus this area of the brain offers the potential for new treatments of these conditions. Clinical trials have begun on certain drugs that have been shown to improve prefrontal cortex function, including [[guanfacine]] which acts through the [[alpha-2A adrenergic receptor]]. A downstream target of this drug, the [[HCN channel]], is one of the most recent areas of exploration in prefrontal cortex pharmacology.<ref>{{cite journal |author=Wang, M. et al. |title=Alpha2A-adrenoceptors strengthen working memory networks by inhibiting cAMP-HCN channel signaling in prefrontal cortex |journal=Cell |volume=129 |issue=2 |pages=397–410 |year=2007 |pmid=17448997 |doi=10.1016/j.cell.2007.03.015}}</ref>

[[Interference theory]] can be broken into three kinds: proactive, retroactive and output. Proactive interference was localized to the ventrolateral and left anterior prefrontal cortex using the “recent-probes” task.<ref>{{cite journal | doi = 10.1016/j.neuroscience.2005.06.042 | author = Jonides J., Nee D.E. | year = 2006 | title = Brain Mechanisms of Proactive Interference in Working Memory | url = | journal = Neuroscience | volume = 139 | issue = 1| pages = 181–193 | pmid = 16337090 }}</ref> Retroactive interference has been localized to the left anterior ventral prefrontal cortex by [[magnetoencephalography]] studies investigating retroactive interference and working memory in elderly adults. The study found that adults 55–67 years of age showed less magnetic activity in their prefrontal cortices than the control group.<ref>{{cite journal | doi = 10.1016/j.neulet.2009.03.087 | author = Solesio E., Lorenzo-López L., Campo P., López-Frutos J.M., Ruiz-Vargas J.M., Maestú F. | year = 2009 | title = Retroactive interference in normal aging: A magnetoencephalography study | url = | journal = Neuroscience Letters | volume = 456 | issue = 2| pages = 85–88 | pmid = 19429139 }}</ref>

==Executive Functions==

The original studies of Fuster and of [[Patricia Goldman-Rakic|Goldman-Rakic]] emphasized the fundamental ability of the prefrontal cortex to represent information not currently in the environment, and the central role of this function in creating the "mental sketch pad". Goldman-Rakic spoke of how this representational knowledge was used to intelligently guide thought, action and emotion, including the inhibition of inappropriate thoughts, distractions, actions and feelings.<ref>{{cite journal | author = Goldman-Rakic PS| year = 1996| title = The prefrontal landscape: implications of functional architecture for understanding human mentation and the central executive | url = | journal = Philos Trans R Soc Lond B Biol Sci | volume = 351 |issue=1346| pages = 1445–53 |pmid=8941956 | jstor=3069191 | doi = 10.1098/rstb.1996.0129 | last2 = Cools | first2 = A. R. | last3 = Srivastava | first3 = K. }}</ref> In this way, working memory can be seen as fundamental to attention and behavioral inhibition. Fuster speaks of how this prefrontal ability allows the wedding of past to future, allowing both cross-temporal and cross-modal associations in the creation of goal-directed, perception-action cycles.<ref>{{cite journal | doi = 10.1038/35012613 | author = Fuster JM, Bodner M, Kroger JK | year = 2000 | title = Cross-modal and cross-temporal association in neurons of frontal cortex | url = | journal = Nature | volume = 405 | issue = 6784| pages = 347–51 | pmid = 10830963 }}</ref> This ability to represent underlies all other higher executive functions.

Shimamura proposed Dynamic Filtering Theory to describe the role of the prefrontal cortex in [[executive functions]]. The prefrontal cortex is presumed to act as a high-level gating or filtering mechanism that enhances goal-directed activations and inhibits irrelevant activations. This filtering mechanism enables executive control at various levels of processing, including selecting, maintaining, updating, and rerouting activations. It has also been used to explain emotional regulation.<ref name="Shimamura">{{cite journal |author=Shimamura, A. P. |title=The role of the prefrontal cortex in dynamic filtering |journal= Psychobiology |volume=28 |pages=207–218 |year=2000 | url=http://socrates.berkeley.edu/~shimlab/2000_Shimamura_DynFilter.pdf | format=PDF}}</ref>

Miller and Cohen proposed an Integrative Theory of Prefrontal Cortex Function, that arises from the original work of Goldman-Rakic and Fuster. The two theorize that “cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represents goals and means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task”.<ref name="MillerCohen">{{cite journal |author=Miller EK, Cohen JD |title=An integrative theory of prefrontal cortex function |journal=Annu Rev Neurosci |volume=24 |issue= |pages=167–202 |year=2001 |pmid=11283309 |doi=10.1146/annurev.neuro.24.1.167}}</ref> Essentially the two theorize that the prefrontal cortex guides the inputs and connections which allows for cognitive control of our actions.

The prefrontal cortex is of significant importance when top-down processing is needed. Top-down processing by definition is when behavior is guided by internal states or intentions. According to the two, “The PFC is critical in situations when the mappings between sensory inputs, thoughts, and actions either are weakly established relative to other existing ones or are rapidly changing”.<ref name="MillerCohen" /> An example of this can be portrayed in the [[Wisconsin card sort|Wisconsin card sort task (WCST)]]. Subjects engaging in this task are instructed to sort cards according to the shape, color, or number of symbols appearing on them. The thought is that any given card can be associated with a number of actions and no single stimulus-response mapping will work. Human subjects with PFC damage are able to sort the card in the initial simple tasks, but unable to do so as the rules of classification change.

Miller and Cohen conclude that the implications of their theory can explain how much of a role the PFC has in guiding control of cognitive actions. In the researchers' own words they claim that “depending on their target of influence, representations in the PFC can function variously as attentional templates, rules, or goals by providing top-down bias signals to other parts of the brain that guide the flow of activity along the pathways needed to perform a task”.<ref name="MillerCohen" />

==Other disorders==

In the last few decades, [[neuroimaging|brain imaging]] systems have been used to determine brain region volumes and nerve linkages. Several studies have indicated that reduced volume and interconnections of the frontal lobes with other brain regions is observed in those with [[Attention Deficit Hyperactivity Disorder]], [[schizophrenia]], [[depression (mood)|depression]], [[bipolar disorder]], people subjected to repeated [[stressor]]s,<ref>{{cite journal |author=Liston C et al. |title=Stress-induced alterations in prefrontal cortical dendritic morphology predict selective impairments in perceptual attentional set-shifting |journal=J Neurosci |volume=26 |issue=30 |pages=7870–4 |year=2006 |pmid=16870732 |doi=10.1523/JNEUROSCI.1184-06.2006}}</ref> [[suicide]] victims,<ref>{{cite journal |author=Rajkowska G |title=Morphometric methods for studying the prefrontal cortex in suicide victims and psychiatric patients |journal=Ann N Y Acad Sci |volume=836 |issue= |pages=253–68 |year=1997 |pmid=9616803 |doi=10.1111/j.1749-6632.1997.tb52364.x}}</ref> incarcerated [[criminal]]s, [[sociopath]]s, lead poisoning,<ref>{{cite journal | author = Cecil KM, Brubaker CJ, Adler CM, Dietrich KN, Altaye M, Egelhoff JC, Wessel S, Elangovan I, Hornung R ''et al.'' | year = 2008 | title = Decreased brain volume in adults with childhood lead exposure | url = | journal = [[PLoS Med]] | volume = 5 | issue = 5| page = e112 | pmid=18507499| doi =10.1371/journal.pmed.0050112 | editor1-last = Balmes | editor1-first = John | pmc = 2689675 }}</ref> and [[drug addict]]s. It is believed that at least some of the human abilities to feel [[guilt]] or remorse, and to interpret [[reality]], lie in the prefrontal cortex.<ref>{{cite journal |author=Anderson SW |title=Impairment of social and moral behavior related to early damage in human prefrontal cortex |journal=[[Nature Neuroscience]] |volume=2 |issue= 11|pages=1032–7 |year=1999 |pmid=10526345 |doi=10.1038/14833 |last2=Bechara |first2=A |last3=Damasio |first3=H |last4=Tranel |first4=D |last5=Damasio |first5=AR}}</ref> It is also widely believed that the size and number of connections in the prefrontal cortex relates directly to [[sentience]], as the prefrontal cortex in humans occupies a far larger percentage of the brain than any other animal. And it is theorized that as the brain has tripled in size over 5 million years of human evolution,<ref>{{cite journal|doi=10.1073/pnas.97.9.4932|last=Schoenemann|first=P. Thomas|coauthors=Thomas F. Budinger, Vincent M. Sarich, William S. Wang|title=Brain size does not predict general cognitive ability within families|journal=[[Proceedings of the National Academy of Sciences of the United States of America]]|date=25|year=2000|month=April|volume=97|issue=9|pages=4932–4937|pmid=10781101|pmc=18335}}</ref> the prefrontal cortex has increased in size sixfold.{{Citation needed|date=October 2009}}

==See also==
* [[Attention versus memory in prefrontal cortex]]
* [[Self-model theory of subjectivity]]

==References==
{{Reflist|2}}

==External links==
{{Commons category|Prefrontal cortex}}
* [http://bama.ua.edu/~sprentic/672%20aggression-brain.jpg Diagram (ua.edu)]
* [http://universe-review.ca/I10-80-prefrontal.jpg Diagram (universe-review.ca)]
* {{BrainMaps|Prefrontal%20cortex|Prefrontal cortex}}

{{Prosencephalon}}

[[Category:Cerebrum]]

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Cerebrum

2011-09-13T13:07:04Z

PhineasG: /* Variation among species */ fixed references

{{Infobox Brain|
Name = Cerebrum |
Latin = |
GraySubject = |
GrayPage = |
Map --[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC) = Cerebrum map|
MapPos = |
MapCaption = The lobes of the cerebral cortex include the [[frontal lobe|frontal]] (blue), [[temporal lobe|temporal]] (green), [[occipital lobe|occipital]] (red), and [[parietal lobe]]s (yellow). The [[cerebellum]] (unlabeled) is not part of the telencephalon. |
Image2 = EmbryonicBrain.svg |
Caption2 = Diagram depicting the main subdivisions of the embryonic vertebrate brain. |
IsPartOf = |
Components = |
Artery = [[anterior cerebral artery|anterior cerebral]], [[middle cerebral artery|middle cerebral]], [[posterior cerebral artery|posterior cerebral]] |
Vein = [[cerebral veins]] |
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BrainInfoNumber = |
MeshName = Telencephalon |
MeshNumber = A08.186.21.730.885 |
NeuroLex = Cerebrum
| NeuroLexID = birnlex_1042 |
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DorlandsSuf = |
}}
The '''cerebrum''' or '''telencephalon''', together with the [[diencephalon]], constitutes the [[forebrain]]. The cerebrum is the most [[anterior]] (or, in humans, most [[Neuroanatomy#Orientation in neuroanatomy|superior]]) region of the [[vertebrate]] [[central nervous system]]. '''Telencephalon''' refers to the embryonic structure, from which the mature '''cerebrum''' develops. In mammals, the [[Dorsum (biology)|dorsal]] telencephalon, or [[Pallium (neuroanatomy)|pallium]], develops into the [[cerebral cortex]], and the [[ventral]] telencephalon, or [[subpallium]], becomes the [[basal ganglia]]. The cerebrum is also divided into approximately symmetric [[Lateralization of brain function|left and right cerebral hemispheres.]]

With the assistance of the [[cerebellum]], the cerebrum controls all voluntary actions in the body.

== Development ==
During vertebrate embryonic development, the [[prosencephalon]], the most anterior of three [[vesicle (biology)|vesicle]]s that form from the [[embryo]]nic [[neural tube]], is further subdivided into the telencephalon and [[diencephalon]]. The telencephalon then forms two lateral telencephalic vesicles which develop into the left and right cerebral hemispheres.

== Structure ==
The cerebrum is composed of the following sub-regions:
* [[Cerebral cortex]], or cortices of the cerebral hemispheres
* [[Basal ganglia]], or basal nuclei
* [[Limbic System]]

== Composition ==
[[File:Cerebrum animation small.gif|thumb|Location of the human cerebrum (red).]]
The cerebrum comprises what most people think of as the "[[brain]]." It lies in front or on top of the [[brainstem]] and in humans is the largest and most well-developed of the five major divisions of the brain. The cerebrum is the newest structure in the [[phylogenetic]] sense, with [[mammal]]s having the largest and most well-developed among all [[species]]. In larger mammals, the cerebral cortex is folded into many gyri and sulci, which has allowed the cortex to expand in surface area without taking up much greater volume.

In [[human]]s, the cerebrum surrounds older parts of the brain. [[Limbic]], [[olfactory]], and [[motor systems]] project fibers from the cerebrum to the [[brainstem]] and [[spinal cord]]. [[Cognition|Cognitive]] and [[volition (psychology)|volitive]] systems project fibers from the cerebrum to the [[thalamus]] and to specific regions of the [[midbrain]]. The neural networks of the cerebrum facilitate complex behaviors such as social interactions, thought, judgement, learning, [[working memory]], and in humans, speech and [[language]].

== Functions ==
'''Note''': As the cerebrum is a gross division with many subdivisions and sub-regions, it is important to state that this section lists the functions that the cerebrum ''as a whole'' serves. See main articles on [[cerebral cortex]] and [[basal ganglia]] for more information.

=== Movement ===
The cerebrum directs the conscious or volitional motor functions of the body. These functions originate within the [[primary motor cortex]] and other frontal lobe motor areas where actions are planned. [[Upper motor neuron]]s in the primary motor cortex send their [[axon]]s to the brainstem and spinal cord to [[synapse]] on the [[lower motor neurons]], which innervate the muscles. Damage to motor areas of cortex can lead to certain types of [[motor neuron disease]]. This kind of damage results in loss of muscular power and precision rather than total [[paralysis]].

=== Sensory processing ===
The primary sensory areas of the [[cerebral cortex]] receive and process visual, auditory, [[somatosensory]], [[gustatory]], and [[olfactory]] information. Together with association cortical areas, these brain regions synthesize sensory information into our perceptions of the world around us.

=== Olfaction ===
{{Main|Olfaction}}
The [[olfactory bulb]] in most vertebrates is the most anterior portion of the cerebrum, and makes up a relatively large proportion of the telencephalon. However, in humans, this part of the brain is much smaller, and lies underneath the frontal lobe. The olfactory sensory system is unique in the sense that neurons in the olfactory bulb send their axons directly to the [[piriform cortex|olfactory cortex]], rather than to the [[thalamus]] first. Damage to the olfactory bulb results in a loss of the sense of smell.

=== Language and communication ===
{{Main|Language}}
[[Speech communication|Speech]] and language are mainly attributed to parts of the cerebral cortex. Motor portions of language are attributed to [[Broca's area]] within the frontal lobe. Speech comprehension is attributed to [[Wernicke's area]], at the temporal-parietal lobe junction. These two regions are interconnected by a large [[white matter]] tract, the [[arcuate fasciculus]]. Damage to the Broca's area results in [[expressive aphasia]] (non-fluent aphasia) while damage to Wernicke's area results in [[receptive aphasia]] (also called fluent aphasia).

=== Learning and memory ===
{{Main|Memory}}
Explicit or declarative (factual) memory formation is attributed to the [[hippocampus]] and associated regions of the medial temporal lobe. This association was originally described after a patient known as [[HM (patient)|HM]] had both his hippocampuses (left and right) surgically removed to treat severe epilepsy. After surgery, HM had [[anterograde amnesia]], or the inability to form new memories.

Implicit or procedural memory, such as complex motor behaviors, involves the basal ganglia.

Short-term or working memory involves association areas of the cortex, especially the [[Neuroanatomy#Orientation in neuroanatomy|dorsal lateral]] part of the [[prefrontal cortex]], as well as the hippocampus.

==Variation among species==
In the most primitive living vertebrates, the [[hagfish]]es and [[lamprey]]s, the cerebrum is a relatively simple structure receiving nerve impulses from the [[olfactory bulb]]. In [[cartilaginous]] and [[lobe-finned fish]]es, and also in [[amphibian]]s, a more complex structure is present, with the cerebrum being divided into three distinct regions. The lowermost (or ventral) region forms the basal nuclei, and contains fibres connecting the rest of the cerebrum to the [[thalamus]]. Above this, and forming the lateral part of the cerebrum, is the ''paleopallium'', while the uppermost (or dorsal) part is referred to as the ''archipallium''. The cerebrum remains largely devoted to olfactory sensation in these animals, despite its much wider range of functions in [[amniote]]s.<ref name="VB" />

In [[ray-finned fish]]es, the structure is somewhat different. The inner surfaces of the lateral and ventral regions of the cerebrum bulge up into the ventricles; these include both the basal nuclei and the various parts of the pallium, and may be complex in structure, especially in [[teleost]]s. The dorsal surface of the cerebrum is membranous, and does not contain any nervous tissue.<ref name="VB" />

In the amniotes, the cerebrum becomes increasingly large and complex. In [[reptile]]s, the paleopallium is much larger than in amphibians, and its growth has pushed the basal nuclei into the central regions of the cerebrum. As in the lower vertebrates, the grey matter is generally located beneath the white matter, but in some reptiles, it spreads out to the surface to form a primitive cortex, especially in the anterior part of the brain.<ref name="VB" />

In [[mammal]]s, this development proceeds further, so that the cortex covers almost the whole of the cerebral hemispheres, especially in more "advanced" species, such as [[primate]]s. The paleopallium is pushed to the ventral surface of the brain, where it becomes the olfactory lobes, while the archipallium becomes rolled over at the medial dorsal edge to form the [[hippocampus]]. In [[placental mammal]]s, a [[corpus callosum]] also develops, further connecting the two hemispheres. The complex convolutions of the cerebral surface are also found only in higher mammals.<ref name="VB" />

The cerebrum of [[bird]]s has evolved along different lines to that of mammals, although they are similarly enlarged, by comparison with reptiles. However, this enlargement is largely due to the basal ganglia, with the other areas remaining relatively primitive in structure. For example, there is no great expansion of the cerebral cortex, as there is in mammals. Instead, an [[High vocal center|HVC]] develops just above the basal ganglia, and this appears to be the area of the bird brain most concerned with learning complex tasks.<ref name="VB" />

== See also==
* [[List of regions in the human brain]]
* [[Cerebral cortex]]
* [[Basal ganglia]]

== References ==
#{{note|VB}} {{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 536–543|isbn= 0-03-910284-X}}

==External links==
* [http://www.rahulgladwin.com/blog/2006/06/cerebrum-higher-integrative-functions.html Cerebrum Medical Notes on rahulgladwin.com]
* [http://www.neuinfo.org/nif/nifgwt.html?query=%22Cerebrum%22 NIF Search - Cerebrum] via the [[Neuroscience Information Framework]]

{{Nervous system}}
{{Cerebral cortex}}
{{Commissural fibers}}
{{Lateral ventricles}}
{{Rostral basal ganglia and associated structures}}
{{Association fibers}}

[[Category:Cerebrum| ]]

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Talk:Lateralization of brain function

2011-09-13T13:02:26Z

PhineasG: /* Connection between Broca's and Wernicke’s */

{{talk header}}
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== Popular meaning ==
Can't the article start with the popular meaning, as a way to debunk it, but still be useful. People every day say "left brained" and I came here to see what it meant and was confronted by a wordy pedantic wordy blah blah wordy yadda yadda wordy digression. Or perhaps just have an article called "left brained" and put in the popular meaning and say "but it ain't true, see lateralization". Wikipedia is getting ruined by amateur pedants.

Disagree. If you want the "popular" meaning based on usage, consult a dictionary. If you want the currently most popular meaning, consult a web-dictionary. Wikipedia strives to be an encyclopedia that indexes and strives toward organization of the knowledgeable, not the knowledge of the man-in-the-street. In any case, there are an almost infinite number of "popular" conceptions about. Which of those do you propose be used? Yours?

==Confusion on lateralization==
I have seen it asserted that scientific research has found that mathematics is done with the left brain. But I wonder whether those whom brain researchers observed "doing mathematics" were doing
* what '''brain researchers''' consider to be "mathematics", or
* what '''mathematicians''' consider to be "mathematics"?
For example, suppose one who has a good handle on the standard first-year calculus course is asked to evaluate the integral
::<math>\int {dx \over (x^2 + 4x + 13)^2}.</math>
I have a deep dark suspicion that some of those brain researchers think that's what mathematics is (it would be a bit like mistaking copy-editing for English literature). On the other hand, suppose a 10-year-old wonders why it is that when you add two odd numbers you get an even number and when you multiply two odd numbers you get an odd number, and figures it out (all 10-year-olds do things like this, except perhaps those who will grow up to be non-mathematicians). That would in fact be mathematics. Likewise, figuring out how to evaluate the integral above without having seen it done in textbooks, as opposed to following the textbook routines, would be mathematics.

So which is it (if either)? [[User:Michael Hardy|Michael Hardy]] 23:05, 27 January 2006 (UTC)

Have a look at [http://scholar.google.com/scholar?hl=en&lr=&q=cache:MHqlXwaDu8YJ:psych.colorado.edu/~dmartich/1001/Singh.pdf+author:%22Singh%22+intitle:%22Interhemispheric+Interaction+During+Global%E2%80%93Local+...%22]
:''These results suggest that enhanced interhemispheric interaction is a unique functional characteristic of the mathematically gifted brain.''
a bit of intensive websearching reaveals a few interesting gems on the subject which I can't remember off hand. I seem to remember finding a study somewhere showing high numbers of left handed in mathematically gifted people.

As you point out there are two different processes going on in mathematics at different levels. There can be intesive symbolic work which fits with the left hemisphere language processing areas. But there is also a more conceptual side possibly requiring right brain processing.

Good to see this article created. I did quite a bit of research on the subject last year and found a whole bunch of interesting stuff have a look at [http://singsurf.org/brain/rightbrain.html].
--[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 23:28, 27 January 2006 (UTC)

::Thank you. [[User:Michael Hardy|Michael Hardy]] 23:58, 27 January 2006 (UTC)

I am being taken to task for suggesting that it is disrespectful to brain researchers who (and I do know this) use sophisticated mathematics, to suggest that in their assertions about which parts of the brain are involved in mathematics, they are applying a childishly simple notion of what mathematics is. But this article as it is now written does encourage that impression. If the impression is wrong, the article should be changed accordingly. [[User:Michael Hardy|Michael Hardy]] 00:00, 28 January 2006 (UTC)
:No one should take you to task; these are important and pertinent points you raise. You may find it useful to look up [[acalculia]]; this is a neurologic finding that can be seen in relative isolation. In clinical practice it refers to difficulty with simple calculation - addition and subtraction, mainly, at least as I have seen it tested. Gerstmann claimed it was related to lesions of the left angular gyrus, but this is probably too specific to be applicable in all cases. -[[User:Ikkyu2|Ikkyu2]] 23:14, 28 January 2006 (UTC)
::Heh. He's referring to [http://en.wikipedia.org/w/index.php?title=User_talk:Michael_Hardy&diff=37013979&oldid=36467040 my comment here] that I left on his user page. As the self-appointed [[Wikipedia:Esperanza|Esperanza]] bouncer I don't take too kindly to perceived intentional rudeness; I am a big fan of the [[Meta:Don't be a dick]] policy. Also, your point on [[acalculia]] (an article I've helped write) is dead on, but still not quite the point Mr. Hardy is getting at methinks. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 23:36, 28 January 2006 (UTC)

:::"Perceived intentional rudeness" was only ''perceived''. Nor do I think there was ''u''nintentional rudeness; someone just misunderstood what I wrote. However, I will admit that if I had written less hastily, I might have anticipated some ways in which my words could get misunderstood and taken care to phrase it differently.

:::"Semiconscious" also seems to think I was "talking at" him, but in fact I have paid close attention to his words. [[User:Michael Hardy|Michael Hardy]] 23:53, 2 February 2006 (UTC)

I'll see if I can add dig up some more references. I'm also concerned about the word '''Reasoning''' in
:''Reasoning functions such as language and mathematics are often lateralized to the left hemisphere of the brain''
from my understanding its more symbolic processing and temporal processing in the left. Reasoning is a little to broad a claim. --[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 00:30, 28 January 2006 (UTC)
::[[User:Pfafrich|Salix alba]]: If you would not mind altering this as well, I would appreciate it. I'm trying to simultaneously do too many real life things to really correct this language right now. See my response below for my thoughts on this article. If you don't get to this in the next few days I should have time next week to dig up better references and resources to more clearly express the notion of laterality of "reasoning" in the brain. Cheers! [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 19:04, 28 January 2006 (UTC)
::: No problem I'll wait. This seem an article very much in gestation at the moment. --[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 19:11, 28 January 2006 (UTC)

== New Scientist 28 Jan 06 ==
Interesting series of articles in this week New Scientist in particular ''Glad to be Gullible'' by ''Clare Wilson''. [http://www.newscientist.com/channel/being-human/mg18925361.300.html].

A few relevant quotes:
*''What determins our tendancy to spot patterns and form associations? It turns out that the key factor is the relative dominance of the right and left hemispheres of the brain. ... Most neuroscientists would accept that the left side of the brain is primarily responsable for language and logical analysis, while the right side is more involved in creativity and what might be called lateral thinking - making connections between disprate concepts''.
*''Several recient studies suggest that people who beleive in the paranomal have greater right brain dominance'' (See Psychiatry Research:Neuorimaging, vol 100, p139 and Psychopathology, vol 34, p75).
*''Brugger and other have shown that there is relativly more right brain activity in people with schizophrenia''

[http://www.neuroscience.unizh.ch/e/groups/brugger00.htm Peter Bruger] a neroscientist at University Hospital, Zurich. Seems a man to watch. --[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 15:25, 27 January 2006 (UTC)

==Long-winded reply==
We are treading dangerously close to semantics here based upon hearsay rather than fact, so I am going to preface this by providing a definition of ''mathematics'' from [http://www.dictionary.com dictionary.com] to ensure we all begin from the same point:
math•e•mat•ics
n. (used with a sing. verb)
# The study of the measurement, properties, and relationships of quantities and sets, using numbers and symbols.
# a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement [syn: math, maths]
[[User:Michael_Hardy] provides one of these two definitions and seems to assign one of them more correctness than the other based upon a non-defined, unreferenced claim of a "mathematicians definition". In fact this notion is furthermore brought forth in Wikipedia's own entry on [[Mathematics]] which suggests (without citing any sources) that ''Another view, held by many mathematicians, is that mathematics is the body of knowledge justified by deductive reasoning, starting from axioms and definitions''. Stating that “many people” hold any particular definition of something is extremely vague and potentially unfounded and inaccurate , but I'll run with it.

[http://www.sciencemag.org/cgi/content/full/284/5416/970 This article from ''Science'' magazine] attempts to describe more precise definitions of "mathematics", suggesting it either has linguistic origins or is more visuo-spatial. The crux of the article suggests there are different forms, what they call "exact arithmetic" and "approximate arithmetic". "Exact arithmetic"--"what brain researchers consider to be mathematics'"--is strongly left-lateralized as this article suggests. "Approximate arithmetic"--"what mathematicians consider to be 'mathematics'"--is bilateral.

Again, in deference to civility, I will amend this article to more clearly state these differences despite my intuition that this is a semantic argument that is unnecessarily clouding what is essentially an already poorly-defined notion. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 00:29, 28 January 2006 (UTC)

::Also, thank you both for coming here to edit this page: if nothing else it is enforcing a more precise definition of the terms we are using. If I am coming across as abrasive, I have no intentions other than clarity and I truly appreciate the efforts here. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 00:37, 28 January 2006 (UTC)

I was not suggesting anything about "approximate" versus "exact". I was suggesting that

* using mathematical methods developed by others in more-or-less mechanical fashion

involves a different kind of thinking from

* actually developing such methods from scratch, regardless of whether that is done by a mathematician breaking new ground or a fourth-grader figuring out without help why it is that when you multiply two odd numbers you always get an odd number, or figuring out, without having heard it asserted by teachers or textbooks or anyone else, that the sum of the angles of a triangle is always 180 degrees.

Those are two different kinds of thinking. The latter is not "approximate". [[User:Michael Hardy|Michael Hardy]] 00:55, 28 January 2006 (UTC)

::What I seem to be poorly expressing here is that--while I understand your point—it is too ill-defined for an encyclopedic article. You have pointed out to me a place where the language is poorly defined and thus open to many interpretations. Therefore I have altered the language acordingly and provided a citation in support of my change. You can continue arguing about your feelings as to what "mathematics" truly is but that is no longer relevant to this article or this discussion as the word "mathematics" or any of its variants no longer appears in the article in any form (other than in the title of reference I provided).
::I further agree with [[User:Pfafrich|Salix alba]] that "reasoning" is a poor word choice as well. In my experience, the casual reader on Wikipedia does not like a great deal of technical language. In my attempt at trying to communicate a relatively simple idea to benefit the maximum number of readers, I chose to use simpler terms. This was clearly not an appropriate choice however, as I was unaware at how poorly defined a term such as "mathematics" was. My point being, you may continue arguing this--and I will gladly engage you in an argument of semantics if you would like--however in the context of this article I consider this issue to be resolved. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 19:01, 28 January 2006 (UTC)

:::I don't think imprecision in the definition of "mathematics" is the issue here at all. It is not easy to define "mathematics", and any definition would be subject to endless debate among informed people (and uninformed ones too, I suppose). But I meant that what actual mathematicians and other actual humans actually do, when doing things that everyone would agree is mathematics, is mostly not algorithmic processing. [[User:Michael Hardy|Michael Hardy]] 01:03, 30 January 2006 (UTC)

A distinction I've always like is betwene Algebra and Geometry. Mathematics can been seen as a process of expressing Geometry in Algebra. Loosly it could be said algebra happens on the left and geometry in the right. (unverified!) --[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 00:57, 28 January 2006 (UTC)

::No -- I don't think so. Algorithmic processing versus creative thinking about mathematics is closer to what I had in mind. The latter is what mathematicians are trying to do; the former is a means. [[User:Michael Hardy|Michael Hardy]] 01:00, 30 January 2006 (UTC)

==Exact/algorithmic/blah blah==
Hardy: Did you read the citation I provided? I was simply using the language they used. You can apply whatever words you'd like to this: it's so nebulously defined that I just really don't care. However I find you use of the phrase "recent discussion tends to confirm my suspicion" in your edit summary amusing, since it was more you talking ''at'' me rather than a discussion. :) [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 00:11, 1 February 2006 (UTC)

::I've looked at it enough to know that it provides some context that aids in understanding what they mean by "exact arithmetic" and that context is not (yet, anyway) in the present Wikipedia article. That article ''and'' the things you and others have said here do tend to confirm my suspicion. It's just as if they were confusing that sort of thinking with what mathematics actually is. [[User:Michael Hardy|Michael Hardy]] 21:26, 1 February 2006 (UTC)

== A cap on discussion ==
Recall that we are editing an assemblage of other people's work here, not conducting original research or trying to form cohesive theories out of disparate publications. Much of the current discussion above would absolutely vanish if the editors would confine themselves to statements developed from and taken directly from source publications, ideally cited by page number and possibly quoted briefly under fair use. -[[User:Ikkyu2|Ikkyu2]] 19:48, 1 February 2006 (UTC)
:Ugh I'm so sick of this. Michael Hardy clearly has strong feelings a '''''his''''' definition of math. After looking over at the [[Mathematics]] article, there's a huge issue with defining mathematis; I'm not sure why Michael Hardy is coming in here and making changes that go against a cited article in ''Science'' inserting his own definition based upon phrases such as "confirm my suspicion" and "what mathematics actually is". These are opinions sir, and not worthy of countering a good citation. I have conceded several times over that my original statement was unclear, so I feel the citation is a good compromise. But you just keep inserting your own personal views on the matter.
:It's [http://en.wikipedia.org/w/index.php?title=Mathematics&diff=11180862&oldid=11180822 clear] you feel strongly on this matter, but others [http://en.wikipedia.org/w/index.php?title=Talk:Mathematics&diff=11160991&oldid=11160652 feel differently] than you and [http://en.wikipedia.org/wiki/Talk:Mathematics#NPOV_and_original_research.3F defining mathematics] is [http://en.wikipedia.org/wiki/Talk:Mathematics#Recent_revert_wars problematic], so please quit reverting based upon your suspicions. Suspicion does not trump citation. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 02:15, 2 February 2006 (UTC)
:::I did not propose any particular definition of mathematics. I don't know why Semiconscious thinks I did. I edited this article for clarity, not to support particular opinions. The only thing I said about the nature of mathematics consisted of a list of '''examples''', not a definition, and I don't think any of them are controversial. Also, to say that mechanically executing algorithms is '''not''' mathematics is also not contrvoersial. [[User:Michael Hardy|Michael Hardy]] 00:03, 16 February 2006 (UTC)

== Recent Brain Research: Fascinating Implications for Educators ==
Found a facinating review of litrature on brain research:
''Recent Brain Research for Teachers & Other Curious Souls''
By Wenda Sheard, J.D., Ph.D. [www.hoagiesgifted.org/Recent%20Brain%20Research.ppt]

Some of the finding include:
*O’Boyle, M. W., Alexander, J. E., & Benbow, C. P. (1991). Enhanced right hemisphere activation in the mathematically precocious: a preliminary EEG investigation. Brain and Cognition, 17(2): 138-153. EEG patterns of LH activation differ in mathematically precocious youth from that of average math ability students. “Enhanced RH involvement during cognitive processing may be a correlate of mathematically precocity.” Three tasks: gaze at blank slide, judge which of two faces was happier, determine if a word is a noun or verb. (EEG, Six mathematically precocious youth mean age 13.2 SAT-Math mean 670, all right-handed, 10-item questionnaire about which hand used when performing tasks. Control group of 8 right-handed males not precocious at math. Eight EEG sites with cap.)
*Raz, N., Torres, I. J., Spencer, W. D., & Millman, D. (1993). Neuroanatomical correlates of age-sensitive and age- invariant cognitive abilities: An in vivo MRI investigation. Intelligence, 17: 407-422. MRI, brain symmetry, 29 subjects ages 18-78. “The magnitude of leftward hemispheric volume asymmetry significantly and uniquely contributed to explaining the variance in both cognitive measures (non-verbal reasoning and vocabulary).
*Alexander, J. E., O’Boyle, M. W., & Benbow, C. P. (1996). Developmentally advanced EEG alpha power in gifted male and female adolescents. International Journal of Psychophysiology, 23(1-2): 25-31. EEG study of 30 gifted adolescents (mean age 13.3, SAT averages 1100), 30 average ability adolescents, and 30 college-age subjects. “(T)here were no significant differences in overall alpha power between college-aged and gifted adolescent subjects. These finding suggest that gifted adolescents may have a developmentally enhanced state of brain activity, one that more closely resembles that of college-age adults to whom they also resemble in terms of cognitive ability.”
*Jausovec, N. (1997). Differences in EEG alpha activity between gifted and non-identified individuals: Insights into problem solving. Gifted Child Quarterly, 41: 26-32. EEG. Seventeen gifted (IQ over 130 WISC, 3 male & 17 female) and 17 non-identified solved four problems. Recorded relaxed and problem-solving mental states, and hemispheric symmetry/asymmetry. Gifted more LH (Left Hemisphere activity) when in relaxed state. Non-identified more LH when in problem-solving state.

--[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 18:48, 15 February 2006 (UTC)

== Split-brain patients: separate article? ==
I think the section "Split-brain patients" warrants an article. Thoughts?

== Lateralization - help request ==
I've been given a rough time by someone arguing that some authors say brain lateralization is an old concept. Is that so, or not?

I need to know the current state of belief about brain lateralization, and how sure or accepted it is in neuroscience/cognitive science, with a few more cites or findings.

If there was a controversy or dispute, but it's no longer in question, or it's been clarified, could a section "Controversy" be added to the article to make it clearer?

Last, I've tidied up the references as a way to say thankyou in advance for any help. The footnote from "Goulven" isn't referenced in the article, someone needs to fix it :)

Many thanks!

[[user:FT2|FT2]] ([[User_talk:FT2|Talk]] | [[Special:Emailuser/FT2|email]]) 11:43, 30 June 2006 (UTC)

:Like most science the answers tend not to be cut and dried. The field it is still very much a work in progress and as functional imaging techniques improve we will begin to learn more about how verious functions are localised in the brian. Its worth reading the rest of this talk page where there are quite a few references which haven't made it into the main article. Alas I have several other projects on the go so I don't have much time to devote to this article. If you can get hold of Goulven it might provide a good summary of recient research. --[[User:Salix alba|Salix alba]] ([[User talk:Salix alba|talk]]) 14:48, 30 June 2006 (UTC)
::But is the principle of higher cognitive functions being lateralized, pretty much established, or still disputed, or disproven? [[user:FT2|FT2]] ([[User_talk:FT2|Talk]] | [[Special:Emailuser/FT2|email]]) 16:19, 30 June 2006 (UTC)

:::It depends on the function. I think you are referring to popular ideas of left and right. Sure there is a lot of nonsense spread by marketeers of various products. Early in the 70s it was left and right brain people, then later people talked about getting a balance by various means (certain machines, drugs, activities). Some old psychology techniques used the left right brain research of early neuroscience. They made all sorts of unfounded claims for methods. I think this could be added into a section. I have a book on popular myths. It may be useful to open a section. I will add something provisionally using the information. Please revert it if you think it is wrong. [[User:Pacificsun|Pacificsun]] 03:18, 19 July 2006 (UTC)

==Lateralization in pop psych and as extended to cultural metaphors?==
I came to this article looking for a critical discussion of the left-brain/right-brain concept as it is misapplied by non-academics (as well, perhaps, as by some people with enough training in psychology to know better). It's common to the point of cliche to say, usually without any scientific evidence, that a particular activity, organization, job, or even a whole person or society is "left brain" or "right brain". I think that this article would benefit by a section or perhaps an external supplemental article on this question.

Here's a citation which gives some examples of what I'm talking about, although it is from the management literature and may be slightly off-target for this article:

Hines, Terence (1987). Left Brain/Right Brain Mythology and Implications for Management and Training. The Academy of Management Review, 12:4, 600-606.

:Excellent call - yes please! Seconded. Some expert....? :) [[user:FT2|FT2]] ([[User_talk:FT2|Talk]] | [[Special:Emailuser/FT2|email]]) 23:24, 2 July 2006 (UTC)

I looked it up and it is good information. I also have other citations to add to the section. I added also the pseudoscience category. This is a category that helps readers browse any articles with pseudoscience issues. Its not a list of pseudosciences and it doesn't mean that lateralization of brain functioning is pseudoscience. Have a good weekend [[User:Matlee|Matlee]] 06:36, 25 August 2006 (UTC)

== copied section ==
:''In a test in which split- brain patients had to match a series of household objects, the left brain would match by function while the right would match by appearance. So, when seeing a cake on a plate, the left brain would connect to a picture of a fork and spoon while the right brain would select a picture of a broad-brimmed hat. This evidence appeared to support the idea of a highly modular brain in which, for example, thinking in logical categories was a strictly left hemisphere function while mental imagery and spatial awareness were handled on the right''

:''But, says Joseph Hellige, a psychologist at the University of Southern California, this picture changed dramatically as soon as brain-scanning experiments began to show that both sides of the brain played an active role in such processes. Rather, it seemed to be processing styles that distinguished the two halves. Under the scanner, [[language]] turned out to be represented on both sides of the brain, in matching areas of the cortex. Areas on the left dealt with the core aspects of speech such as [[grammar]] and [[word]] production, while aspects such as [[Intonation (linguistics)|intonation]] and [[emphasis]] lit up the right side. In the same way, the right brain proved to be good at working with a general sense of space, while equivalent areas in the left brain fired when someone thought about objects at particular locations.''

Copied from http://www.rense.com/general2/rb.htm --[[User:Tgr|Tgr]] 09:09, 10 December 2006 (UTC)

== InternetHero's edits ==
[[User:InternetHero]] keeps adding the phrase "science of math" to the list of things allegedly done by the left brain. Simple arithmetical calculations are not science. Mathematics, on the other hand, is by some reasonable definitions, science.

In 3rd grade you're told that 5 × 3 is

: 3 + 3 + 3 + 3 + 3

whereas 3 × 5 is

:5 + 5 + 5.

You're '''also''' told that not only do those yield the same number, but that that holds generally, with any other numbers.

If you figure out why that pattern holds generally, you're doing mathematics. But if you develop calculation skills without understanding such things, you're '''not''' doing mathematics, let alone "science of mathematics". [[User:Michael Hardy|Michael Hardy]] 20:45, 19 February 2007 (UTC)

:The concept of multiplication. Do you understand the brain or just math? Please answer honestly.

:Again, I think zinc ions are relevent here. I really don't understand the sloppiness and disregard for basic courtesy in your edits. I will revert from editing untill properly designated, but seriously for almost everyone except overly reformative mathematicians, the ability of arithmetic is in strong relation to math.

:Also, are you denying Benjamin Peirce's words: "the science that draws necessary conclusions". [[User:InternetHero|InternetHero]]--23:31, 27 March 2007 (UTC)

Please see science. Hi, sorry for not discussing with you 1st, but I didn't know you could.

The broadness of science and it's many sub-catogories derived from it's autonomity/abstractness, were meant to be pertained in respect to the concepts of contrast and/or comparison. As you state, the reasonable/logical properties of mathematics can be attributed to both sides of the corpus.

I've made myself a folly. I got 2 attached and let my perogatives take over my reasoning in respect to putting science in both charts. I got attached to this because of the other edit which entitled: Science of Math - Science of Philosophy.

As Michael pointed out, both sides can bi-laterally comprehend mathematical concepts. I was wrong.

Science can constitute any system of objective knowledge - which in this case, refers to the 'system' of simple-algoritmic proccesses via the system of transducing of stimuli.

1) "simple computations are not "science"; 2) mathematics does not consist of simple algorithmic processing"

i) Wiki - Scientific Method: It is based on gathering observable, empirical, measurable evidence, subject to the principles of reasoning.

ii) Wiki - Mathematics: Is the body of knowledge centered on concepts such as '''quantity, structure, space, and change''', and also the academic discipline that studies them.

When savants draw a picture of a buildings window patterns, they can't process concepts like Base x Height. The can individually count or 'grasp' all the windows as a whole, and draw them in that respect. If this process is not a matter of the concepts bolded above, then I don't know what is. [[63.135.9.214]]/[[InternetHero]] 05:01, 19 February (UTC)

==Semantic and Episodic memory==
They both are used my the temporal lobe also:

''"The medial temporal lobes (near the Sagittal plane that divides left and right cerebral hemispheres) are thought to be involved in '''episodic/declarative memory'''. Deep inside the medial temporal lobes, the hippocampi seem to be particularly important for memory function - particularly transference from short to long term memory and control of spatial memory and behavior."'' [http://www.sci.uidaho.edu/med532/temporal.htm]

You guys make a conclusion for yourselves, but I think theres something here. For instance, it states above that the Sagittal plane involves episodic memory, yet is involved in semantic memory as a pre-requisite of declarative memory (Declarative: Semantic/Episodic).

[http://en.wikipedia.org/wiki/Declarative_memory]

This can also be related to left-handed people and this article:

''"In 2006, researchers at Lafayette College and Johns Hopkins University in a study found that left-handed men are 15% richer than right-handed men for those who attended college, and 26% richer if they graduated. The wage difference is still unexplainable and does not appear to apply to women.[26]

As well as possible intelligence advantages, being left-handed can also bring about other benefits, including:

Brain hemisphere division of labor: The premise of this theory is that since both speaking and handiwork require fine motor skills, having one hemisphere of the brain do both would be more efficient than having it divided up.[citation needed]
Advantage in hand-to-hand combat: Left-handers have a 'surprise' factor in combat, since the majority of the population is right-handed."'' [http://en.wikipedia.org/wiki/Left-handed]
- [[User:InternetHero]] 17:33, 16 April, 2007 (UTC)

== Pseudoscience category? ==

:Hines (1987) states that the research on brain lateralization is valid as a research program, though it has been applied to promote subjects and products far out of the implications of the research. For example, the implications of the research have no bearing on psychological interventions such as [[EMDR]], brain training equipment, or management training. One explanation for being so prone to exaggeration and false application is that the left-right brain dichotomy is an easy-to-understand notion, yet is often grossly oversimplified and misused for promotion in the guise of science. This is often known as right-brain mythology, and is associated with occult notions such as yin/yang, righteous and sinister, and day and night. The research on lateralization of brain functioning is ongoing, and its implications are always tightly delineated, whereas the pseudoscientific applications are exaggerated, and applied to an extremely wide range of situations. Hines, Terence (1987). Left Brain/Right Brain Mythology and Implications for Management and Training. The Academy of Management Review, 12:4, 600–606.

:I moved the above section here for discussion. I don't think this article should be in the pseudoscience category. I have removed it. But wanted to open a discussion here and past this paragraph that I cut from the article. Is this really necessary? --[[User:Comaze|Comaze]] 15:12, 26 June 2007 (UTC)

::I think that it's important that such material be here, given that there is a popular misconception about the "left-brain/right-brain" sort of research. There is clearly a real, and proper scientific research program going on regarding the relative strengths and capacities of the cerbral hemispheres (i.e., left for language production, dating back to Broca, or the preponderance of right sided lesions leading to neglect) which serious cognitive neuroscientists recognize as part of their domain. However, that research has largely caught the attention of the general public in a watered down, distorted manner, and I think that it is important to mention this not as a piece of congitive neuroscience, but as a piece of sociology of how scientific findings are dissemenated and used by the general public. I agree, however, that laterlazation of brain function is not pseudoscience, and agree that the cat should be removed. [[User:Edhubbard|Edhubbard]] 00:35, 27 June 2007 (UTC)

:::I think the text needs to be summarised and put in the main body somewhere. We do need to be careful because most functions that are popularly thought of as lateralised are present in both sides of the brain. However, in general the left-hemisphere tends to be dominant for logic, language whereas the right hemishpere tends to be dominant for non-linguistic functions (visualisation, mental rotation, face recognition, etc.)(p.7 ''Western et al. 2006 "Psychology: Austraian and New Zealand edition" John Wiley''). So the popular understanding is not too far off the mark. --[[User:Comaze|Comaze]] 04:56, 27 June 2007 (UTC)

The reference of Hines definitely says its used in a pseudoscientific way if too broad. I will have a look at the rules for inclusion to the pseudoscience category though. I am working in neuroscience research and there is a big complaint by neuroscientists about people saying pseudoscientific things about hemisphericity. Its big issue and is taught at university level. So neuroscientists and science thinkers like Hines want to say that there is a big pseudoscience problem here in this small area of hemisphericity because of commercial persuasion. But they do not say there is a pseudoscience problem generally in neuroscience. [[User:Matlee|Matlee]] 05:57, 27 June 2007 (UTC)

:I can understand why you want to warn people about the mythology in brain sidedness. There are people running around saying that people are more left or right brained, etc. However, I'm not convinced that this article should be in the pseudoscience category. Nor am I convinced of the reliability or authority of Hines as a source for this article. Besides, the main issues are covered in the lead. It now says something like the popular lateralised functions are actually located on both sides of the brain. --[[User:Comaze|Comaze]] 06:33, 27 June 2007 (UTC) Perhaps we could have paragraph covering the left-right sidedness myths with appropriate evidence. --[[User:Comaze|Comaze]] 06:41, 27 June 2007 (UTC)

::Ok I'll look for more sources but I think the Academy Management Review is good enough. I kept some references from a seminar I went to on this problem and will check them. There were also some more commercial examples who use the pseudoscience ideas listed. I might have a look on the web because I am sure its a getting more popular problem. Do you know of any other area that might use myths? I have some idea but not sure about the sort of range. [[User:Matlee|Matlee]] 06:49, 27 June 2007 (UTC)

:::Thanks. These left/right brain myths pop up in teaching, adult education and management training. Best --[[User:Comaze|Comaze]] 07:19, 27 June 2007 (UTC)

:::I think there are two seperate issues here. One is the category tag, which I should stay removed (good spot Comaze), since it seems to apply to the whole article, while it is only this one section that is ''potentially'' pseudoscientific. As I noted above, there is some scientific truth to the idea that the hemispheres do slightly different things, but that has been '''radically''' oversimplified, to the point of potential misrepresentation in the eyes of the generral public. I think Matlee is right to emphasize the word '''dominant''', which is exactly what is missing from much of the pop-culture discussions of lateralization of brain function. As for the actual content, I think that we should probably use more up-to-date and more cognitive neuroscience references, of which I can suggest three good ones here off the top of my head:
:::*J. Graham Beaumont (1983). ''Introduction to Neuropsychology.'' The Guilford Press. ISBN 0898625157. - This book is a bit dated (he is working on an updated version) but his discussion of the link between lesions of the left or right hemisphere, language and handedness is some of the most detailed and complete in the textbook world.
:::* Michael S. Gazzaniga, Richard B. Ivry, George R. Mangun (2002). ''Cognitive Neuroscience, Second Edition.'' W. W. Norton & Company ISBN 0393977773. - This is the textbook that we used when I was an undergraduate, and will be one of the two texts that I will use (along with Ramachandran's ''Phantoms in the Brain'') when I teach my own class. It includes a seperate chapter on lateralization of brain function (Ch. 9), but also treats lateralization in the appropriate places, along with the relevant topics. They are currently working on a third edition. Note, also that Ivry and Robertson have a more integrated account of how such differences might arise from low-level differences in the spatial and temporal frequencies preferentially treated by the two hemispheres (''The Two Sides of Perception'', 1997 MIT Press) although this is probably beyond the scope of the current article. Also, of course, there is a thorough treatment of split-brain work here, given that Gazzaniga is first author.
:::*Jamie Ward (2006). ''The Student's Guide to Cognitive Neuroscience.'' Psychology Press. 1841695343. The most recent cognitive neuroscience textbook on the market, and one that is unique in that, it is the only one (so far) to have chapters on topics like the cognitive neuroscience of reading and numerical cognition (Chs. 11 and 12, respectively). It also tends to place more emphasis on neuropsychological methods than does the Gazzaniga text (which is why I would supplement Gazzaniga with Ramachandran). Again, there's no separate chapter on lateralizaition of function, but the lateralizations of these functions are treated within the appropriate contexts.
::: The important thing to me is that we, in some way, point out this more subtle point. One hemisphere or the other can be dominant for a given function, this varies by handedness, by sex, etc, but at the same time, there is a lot of this type of stuff that has been radically oversimplified in the public literature, since the earliest discoveries of some of these divisions of labor in the human brain. [[User:Edhubbard|Edhubbard]] 07:28, 27 June 2007 (UTC)

Inferior, terrible, dumb? I don't understand how the evaluative words can be used in the overall category. [[User:72.189.94.109|72.189.94.109]]gurbinav

== external links ==

 
One of the current external links on the site:

* [http://www.everux.com/ura/lbrain_or_rbrain.html Left Brain/Right Brain Visual Aptitude Test]

links to an adult site. From my brief check, the site only has this one page on lateralization as it pertains to this article. While it's an interesting graphic, and it has something to do with left and right as concepts, I don't see any reason for its inclusion in this article. Its claim to be a diagnostic tool for determining left/right dominance ("If [you see the image turning] clockwise, then you use more of the right side of the brain and vice versa."), is unsupported AFAIK. I will remove it if there are no objections. [[User:Aaron.michels|Aaron.michels]] ([[User talk:Aaron.michels|talk]]) 19:00, 16 April 2008 (UTC)
:This is a pretty clear case of an inappropriate external link. Feel free to remove this and any other clear violations. --[[User:Gimme danger|Gimme danger]] ([[User talk:Gimme danger|talk]]) 23:31, 16 April 2008 (UTC)

==Mathematics==

Singular concepts of relativity such as counting (not division where a placeholder is needed) would allow the ions/synaptic plasticity to require certain regions of the brain to be used as a prerequite '''in''' the left brain. It all depends on which part of the brain the person uses, but I'm pretty sure the Corpus is the divisor/placeholder so most of the counting/multiplying wouldn't occur there. You might be able to count holistically like [[savant]]s, but I'm useless in that department as I am not a scientist conducting experiments. [[User:InternetHero|InternetHero]] ([[User talk:InternetHero|talk]]) 02:01, 30 June 2008 (UTC)

I've reverted certain of InternetHero's revisions, sorry, as Dehaene ''et al.'' does not address sidedness of counting, measurement, or perception of shapes or motions. Is there a reason the table lists "perception of counting/measurement" as opposed to simply "counting/measurement"? —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Grothmag|Grothmag]] ([[User talk:Grothmag|talk]] • [[Special:Contributions/Grothmag|contribs]]) 22:26, 1 July 2008 (UTC) 
:The problem really isn't the citations; as they are perfectly reasonable for discussing lateralization of mathematics, but rather the qualifiers of "perception of counting/measurement". I've reinstated the refernces, and put in more precise qualifiers, since at least certain aspects of mathematics ("direct retrieval" as we do with times tables) do appear to be uniquely left-hemisphere lateralized, while other aspects of mathematics, including approximate calculation, comparison and so on, appear to depend on both the left and the right hemisphere. Incidentally, although Dehaene's research does not directly address "perception of shapes or motions [sic]" there is plenty of evidence that demonstrates that visual processing of these features is indeed bilateral (see for example, MT/V5 for processing of motion and LOC for shape). [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 02:17, 2 July 2008 (UTC)

== discrepancy - table/text ==
I just wanted to repeat a remark I made in the ''Cerebral hemisphere'' talk page ([[Talk:Cerebral_hemisphere#table_is_too_general?]]), because it also applies to this article. There is a discrepancy in the presentation: On the one hand it is claimed that popular psychology overemphasizes the lateralization of broadly defined concepts such as logic and intuition, on the other hand the upper half of the table in the section "Which side?" is doing just the same. --[[Special:Contributions/88.72.195.165|88.72.195.165]] ([[User talk:88.72.195.165|talk]]) 17:13, 8 July 2008 (UTC)
: Agreed. And the references are from similar non-reliable sources. I think an expert opinion is required, perhaps a neurologist. The table has no place in an article about the verifyable neuroscience anatomy of the brain, it is decidedly outof place. Perhaps the table should be moved into a separate article about popular neuroscience myths. --- [[User:Roidroid|Roidroid]] ([[User talk:Roidroid|talk]]) 13:50, 27 August 2009 (UTC)
:: Hang on... The discrepancy between the "pop-science" lateralization story and the peer-reviewed [[cognitive neuroscience]] understanding of lateralization is a little more subtle than either of you seem to understand. In short, the problem is not that the hemispheres specialize for certain things, which is supported by a host of evidence, going back over 100 years, but rather that this fact has somehow been translated into the idea that there are "left-hemisphere" people and "right-hemisphere" people. This radical oversimplification of the real evidence from neurology and cognitive neuroscience is what is at issue in several places throughout wikipedia. But, the basic information in the table does not fall prey to that oversimplification. Additionally, Roidroid suggests that the references are non-reliable, but from what I can see, the majority of the references in the article and in the table come from peer-reviewed journals, such as ''Science'' (reference 10), ''Cognitive Neuropsychology'' (reference 11), ''Brain'' (reference 16), and textbooks like ''Psycholinguistics: Learning and using Language'' (reference 15) and ''Principles of Neural Science'' (reference 16). I would agree that the first three lines of the table have to go, but not the entire table. I have removed them, and as such, I am removing the pseduoscience tag. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 12:55, 28 August 2009 (UTC)
::: This seems good now [[User:Roidroid|Roidroid]] ([[User talk:Roidroid|talk]]) 05:25, 21 September 2009 (UTC)

::::I was mainly concerned with the removed parts of the table. As far as I understand it the case for lateralization of verbal processing is strong. Numerical processing possibly but I don't know about that. --[[Special:Contributions/88.74.56.40|88.74.56.40]] ([[User talk:88.74.56.40|talk]]) 21:04, 30 September 2009 (UTC)

== Mathematics ==

Under "left", we find:
:
: mathematics (exact calculation, numerical comparison, estimation)
:
and under "right", we find:
:
: mathematics (approximate calculation, numerical comparison, estimation).
:
Obviously this excludes most of mathematics. Calculation, estimation, and comparison are only a tiny tiny part of all of mathematics. Can more be said, or is that unknown? [[User:Michael Hardy|Michael Hardy]] ([[User talk:Michael Hardy|talk]]) 01:57, 25 October 2008 (UTC)

:Maybe "arithmetic" would be better than "mathematics" here. Unfortunately, I'm not familiar with the sources that are cited for that entry in the table. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 05:53, 25 October 2008 (UTC)
::Yes, I agree that arithmetic would be better than mathematics. In fact, the truth of the matter is that there have been very few studies of anything "higher-level" than basic addition, subtraction and multiplication. The only lab that has taken on even basic algrebra is John Anderson at Carnegie Mellon University. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 04:38, 27 October 2008 (UTC)

OK, a favorite example of mine from "arithmetic":
:
: 3 × 5 means 5 + 5 + 5;
: 5 × 3 means 3 + 3 + 3 + 3 + 3.
:
: '''Why must these two ''differently'' defined things always be the ''same'' number, not only with this particular pair of numbers, 3 and 5, but also with any other pair?'''
:
It's not too hard to answer that question. And it's not too hard to ask that question, when, in childhood, one first learns the definitions. Any child who is curious about math is likely to ask that question, and with a bit more effort to answer it. Now when one thinks it through and figures out what the answer is, then what one is doing is '''mathematics''', and by some definitions, is '''arithmetic'''. But it is '''not''' numerical computation; of either an exact kind or an approximate kind. You don't need to ask about more advanced mathematics than that to see the issue here. The right word for what the article talks about is neither "mathematics" nor "arithmetic"; it is "numerical computation" or "calculation" or the like. [[User:Michael Hardy|Michael Hardy]] ([[User talk:Michael Hardy|talk]]) 03:32, 29 October 2008 (UTC)
:Are you talking about this Wikipedia article or about the Dehaene papers that are being referenced? Anyway, I sort of see what you are saying, but I don't think it's necessarily safe to assume that the brain makes the same distinctions that seem correct philosophically. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 05:01, 29 October 2008 (UTC)
::I think that Michael is referring to the word choice, by pointing out that even what we would typically include under the heading of "aritmetic" is much more complex than what has been done in most imaging studies, due to the technical limitations of the method. So, perhaps something like "calculation" rather than "mathematics"?
::On the scientific point, the closest thing to the type of analysis that Michael is thinking of is work that has been done by John Anderson's group at CMU, where they looked at multidigit multiplication and tested so-called "novice" (right-to-left) computation and "expert" (left-to-right) computation (presented as a poster at last year's Cognitive Neurosocience Society meeting in SF, not yet peer-reviewed to my knowledge). This jumps even beyond the level of analysis Michael is thinking of, but I don't think the exact question he is asking has been addressed using any techniques that allow us to infer lateralization. The general inference is that these simpler tasks, like those used by Dehaene or Brian Butterworth's work in patients, allow us to infer what the substrates of more complex processes may be, but this is an inference. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 14:08, 29 October 2008 (UTC)
:::Actually, going back to Michael's initial point, maybe the best thing would be to call this "numerical cognition"? In that case, we make it clear that we are referring to basic numerical processes, since things like comparison and estimation (that is, estimating the number of objects visually seen, not approximate calculation, which is listed seperately) do not even really rise to the level of "computation". [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 14:11, 29 October 2008 (UTC)

== mentioned in A Scanner Darkly movie and book ==

popculture sub heading

(side note: I am reading a lot of left hemisphere shatter and you guys need to chill and enter the world of the right hemisphere.Grays upon grays.) —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/137.186.195.16|137.186.195.16]] ([[User talk:137.186.195.16|talk]]) 11:16, 1 January 2009 (UTC) 

== Merge with Cerebral Hemispheric Dominance ==

It has been suggested that the article [[Cerebral Hemispheric Dominance]] be merged with this one. I personally dont agree. Dominance and Lateralization are 2 completely different topics.[[User:Em3ryguy|just-emery]] ([[User talk:Em3ryguy|talk]]) 18:46, 1 June 2009 (UTC)

Definitely maintain the separation. Where to put the dominance article without getting into the pseudoscience/ pop-psych debate further would be hard to establish. —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/163.238.46.58|163.238.46.58]] ([[User talk:163.238.46.58|talk]]) 18:03, 12 August 2009 (UTC) 
: In fact, just a quick look at the cerebral hemispheric dominance article suggests that it is a collection of the worst pop-psych misinformation about the cerebral hemispheres around (the whole basic idea that there are "left-brained" and "right-brained" people being the biggest one), contributed almost exclusively by one editor in the course of two days. I don't think that article should be merged with this one, and in fact, think that the article, although having some [[WP:RS|reliable sources]] should probably be deleted, or massively re-written to get rid of the pop-psych "neuromyths" [http://www.oecd.org/document/63/0,3343,en_2649_35845581_34555007_1_1_1_1,00.html] [http://www.psychology.heacademy.ac.uk/plat2006/assets/presentations/Goswami/GoswamiNRN2006.pdf] [http://clive-shepherd.blogspot.com/2007/06/neuromyths.html][http://www.eric.ed.gov/ERICWebPortal/custom/portlets/recordDetails/detailmini.jsp?_nfpb=true&_&ERICExtSearch_SearchValue_0=EJ210602&ERICExtSearch_SearchType_0=no&accno=EJ210602]. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 19:00, 12 August 2009 (UTC)
::I don't actually see any valid content in [[Cerebral Hemispheric Dominance]] that would be worth merging. I left a message at the creator's talk page ([[User talk:Julie.summey]]) saying so, but she never responded, consequently the article never came up on my watchlist again, and I forgot about it. I would favor turning it into a redirect. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 19:22, 12 August 2009 (UTC)
::: I tend to agree... the only way to save that article is to make it clear that this is a sort of pop-psych fallacy. I think that this has already been noted in other places, but it might be worth mentioning explicitly in an article with that title. Or, it could just be too much hassle and a fight to keep it. If we have some people that are willing to take it on, then it might be a service the wikipedia using world to make sure that it's clear that this is a popular misconception, but a misconception nonetheless. Otherwise, just redirect here and include some discussion of the fact that these are popular misconceptions? [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 19:28, 12 August 2009 (UTC)

:::: I agree with Looie. There's no real science here, just pop-psych, and the content already present at Lateralization of Brain Function is better science, better explained, and better referenced. I would support deleting this article and turning it into a redirect to both the neuromyths article (if we can do that) and the lateralization article. [[User:Mirafra|Mirafra]] ([[User talk:Mirafra|talk]]) 20:10, 12 August 2009 (UTC)

:::::I think merging (on paper) is better - I doubt an AfD would reach consensus and the result would likely be a merge anyway. I have not looked at the articles in detail - I just woke up and require coffee to get my hemispheres working more..... [[User:Casliber|Casliber]] ([[User talk:Casliber|talk]] '''·''' [[Special:Contributions/Casliber|contribs]]) 20:50, 12 August 2009 (UTC)

I moved the article to the correct title (lower-case initials) and did some copy-editing on it, bringing it closer to the norms of [[WP:MOS]]. I looked at the history and found that the person who wrote it hasn't done anything else on Wikipedia. I sent her an email saying two concerns had been expressed in regard to the article: that it should get merged into this one, and that few other articles link to it (just one, actually). [[User:Michael Hardy|Michael Hardy]] ([[User talk:Michael Hardy|talk]]) 21:02, 12 August 2009 (UTC)

== The Master and His Emissary ==

''[[The Master and His Emissary]]: The Divided Brain and the Making of the Western World'' is a new study of the specialist hemispheric functioning of the brain, and the conflict between their world views, by the psychiatrist and writer Iain McGilchrist. Published 2009. [[User:Esowteric|Esowteric]]+[[User talk:Esowteric|Talk]] 16:13, 21 December 2009 (UTC)
: As ''The Economist'' notes in their review, McGilchrist seems to take astonishingly liberties with the scientific literature [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 18:00, 22 December 2009 (UTC)
::But the reader is also treated to some very loose talk and to generalisations of breathtaking sweep. The left’s world is “ultimately narcissistic”; its “prime motivation is power”, and the Industrial Revolution was, in some mysterious sense, the left’s “most audacious assault yet on the world of the right hemisphere”. The sainted right, by contrast, has “ideals” that are in harmony with an “essentially local, agrarian, communitarian, organic” conception of democracy... But he offers no evidence that such differences can be explained in physiological terms... The book ends with a deflating admission that will not surprise those readers who feel the author’s main claims about the cerebral hemispheres have the ring of loose analogies rather than hard explanations. Mr McGilchrist would not be unhappy to learn that what he has to say about the roles of the hemispheres in Western culture is simply a metaphor and is not literally true. In other words, he seems to be in two minds about his own thesis, which is fitting but not encouraging.
:::Have expanded and balanced the article a bit now. Apparently the philosopher [[Mary Midgley]] will be reviewing the book in [[The Guardian]] in early January 2010. Will see what she has to say. [[User:Esowteric|Esowteric]]+[[User talk:Esowteric|Talk]] 19:31, 25 December 2009 (UTC)
* The book is published by [[Yale University Press]]. That is a [[Wikipedia:NPOV#Explanation_of_the_neutral_point_of_view|significant]] publisher. Whether we think it is hard science, metaphor or philosophy, a book by them addressing this specific topic is a RS and a bona fide addition. --'''[[User:Jayen466|JN]][[User_Talk:Jayen466|466]]''' 20:41, 25 December 2009 (UTC)
::Actually, it does matter. See [[WP:FRINGE]] and [[WP:UNDUE]]. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 02:49, 27 December 2009 (UTC)
::: To clarify, it does not matter for the entry on the book, itself. We should have an entry on the book. But, given that this book does not purport to actually provide any factually correct information on the topic of ''this article'', lateralization of brain function, but rather uses it as a "loose analog[y]" or a "metaphor" that is "not literally true", it should not be included on ''this page'' due to the wikipedia policies cited above. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 02:53, 27 December 2009 (UTC)
::::'''Comment''' What we're talking about here is my attempt to include the book in "further reading", an action that was [http://en.wikipedia.org/w/index.php?title=Lateralization_of_brain_function&action=historysubmit&diff=333312394&oldid=333115114 reverted]. I can appreciate your desire to keep what you see as "poppsych" weeded out of the article, so that it is not flagged as "pseudoscience" (whilst remembering that this is not someone's "recommended reading list" but a representative list of "further reading"). However, I think it's a little unfair to base your judgement on the reaction of a reviewer in ''The Economist''. The [http://www.iainmcgilchrist.com/The_Master_and_his_Emissary_by_McGilchrist.pdf introduction to the book (pdf)] seems to paint a different picture of the book's actual content.
::::I like to run articles past their subjects and the author points out to me that "As to the neuropsychological, neurophysiological and other evidence, there are about 3,000 references to the literature included in the notes", and he himself dismisses what he sees as some popular misconceptions about lateralization, though I am reliant on input from reliable sources and cannot of course use phrases like "meticulously documented" until reliable sources use such phraseology. Further reading could perhaps be split into "mainstream" and "<strike>fringe</strike>" "popular psychology" (again remembering that heliocentricity was at one time dismissed as "fringe" theory :)), if it can be established that this is fringe theory, in order not to give undue weight to the less popular mainstream. Just a thought, [[User:Esowteric|Esowteric]]+[[User talk:Esowteric|Talk]] 11:26, 27 December 2009 (UTC)
:None of the reviewers appear to have scientific credentials, as far as I can see. A book of this sort is likely to be reviewed by ''Science'' or ''Nature'' soon, if it hasn't been already, and reviews there would give a much better idea of whether this is a suitable book to direct readers toward for further information. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 14:49, 27 December 2009 (UTC)
::Yes, that seems fair enough. [[User:Esowteric|Esowteric]]+[[User talk:Esowteric|Talk]] 15:01, 27 December 2009 (UTC)

== Connection between Broca's and Wernicke’s ==

Moved existing comment from the article to here: [[Special:Contributions/69.62.226.199|69.62.226.199]] ([[User talk:69.62.226.199|talk]]) 22:30, 23 May 2010 (UTC)
:The first sentence Area and Wernicke’s Area are linked by a white matter fiber tract, the arcuate fasciculus.is explicitly negated in this article http://en.wikipedia.org/wiki/Arcuate_fasciculus.
[edit]

::The article [[Arcuate fasciculus]] explicitly states (cited) that, while it was believed to connect Broca's area and Wernicke's area, it is no longer believed to do so. I don't have the time now to figure out what should be incorporated into this article, but I did want to be sure to bring it to the attention of hopefully anyone involved with this page. -- [[User:Natalya|Natalya]] 21:35, 12 July 2011 (UTC)

:::I think the truth is that the cellular-level synaptic connections and boundaries of Broca's, Wernicke's, and really any other area of the cortex are poorly understood, and therefore an accurate but still helpful statement might be, e.g., "the arcuate fasciculus connects the lateral prefrontal cortex (including Broca's area) with the posterior parietal and temporal cortex (including Wernicke's area) and has been shown to play a role in language processing." (See, e.g., Catani et al 2007<ref name="Catani et al 2007">{{Cite pmid|17939998}}</ref>.) [[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 15:01, 12 September 2011 (UTC)

<references />

Cerebrum

2011-09-13T12:53:54Z

PhineasG: removed irrelevant x. laevus regeneration section and unused references; added 1 sentence about working memory and prefrontal cortex.

{{Infobox Brain|
Name = Cerebrum |
Latin = |
GraySubject = |
GrayPage = |
Map --[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC) = Cerebrum map|
MapPos = |
MapCaption = The lobes of the cerebral cortex include the [[frontal lobe|frontal]] (blue), [[temporal lobe|temporal]] (green), [[occipital lobe|occipital]] (red), and [[parietal lobe]]s (yellow). The [[cerebellum]] (unlabeled) is not part of the telencephalon. |
Image2 = EmbryonicBrain.svg |
Caption2 = Diagram depicting the main subdivisions of the embryonic vertebrate brain. |
IsPartOf = |
Components = |
Artery = [[anterior cerebral artery|anterior cerebral]], [[middle cerebral artery|middle cerebral]], [[posterior cerebral artery|posterior cerebral]] |
Vein = [[cerebral veins]] |
BrainInfoType = |
BrainInfoNumber = |
MeshName = Telencephalon |
MeshNumber = A08.186.21.730.885 |
NeuroLex = Cerebrum
| NeuroLexID = birnlex_1042 |
DorlandsPre = |
DorlandsSuf = |
}}
The '''cerebrum''' or '''telencephalon''', together with the [[diencephalon]], constitutes the [[forebrain]]. The cerebrum is the most [[anterior]] (or, in humans, most [[Neuroanatomy#Orientation in neuroanatomy|superior]]) region of the [[vertebrate]] [[central nervous system]]. '''Telencephalon''' refers to the embryonic structure, from which the mature '''cerebrum''' develops. In mammals, the [[Dorsum (biology)|dorsal]] telencephalon, or [[Pallium (neuroanatomy)|pallium]], develops into the [[cerebral cortex]], and the [[ventral]] telencephalon, or [[subpallium]], becomes the [[basal ganglia]]. The cerebrum is also divided into approximately symmetric [[Lateralization of brain function|left and right cerebral hemispheres.]]

With the assistance of the [[cerebellum]], the cerebrum controls all voluntary actions in the body.

== Development ==
During vertebrate embryonic development, the [[prosencephalon]], the most anterior of three [[vesicle (biology)|vesicle]]s that form from the [[embryo]]nic [[neural tube]], is further subdivided into the telencephalon and [[diencephalon]]. The telencephalon then forms two lateral telencephalic vesicles which develop into the left and right cerebral hemispheres.

== Structure ==
The cerebrum is composed of the following sub-regions:
* [[Cerebral cortex]], or cortices of the cerebral hemispheres
* [[Basal ganglia]], or basal nuclei
* [[Limbic System]]

== Composition ==
[[File:Cerebrum animation small.gif|thumb|Location of the human cerebrum (red).]]
The cerebrum comprises what most people think of as the "[[brain]]." It lies in front or on top of the [[brainstem]] and in humans is the largest and most well-developed of the five major divisions of the brain. The cerebrum is the newest structure in the [[phylogenetic]] sense, with [[mammal]]s having the largest and most well-developed among all [[species]]. In larger mammals, the cerebral cortex is folded into many gyri and sulci, which has allowed the cortex to expand in surface area without taking up much greater volume.

In [[human]]s, the cerebrum surrounds older parts of the brain. [[Limbic]], [[olfactory]], and [[motor systems]] project fibers from the cerebrum to the [[brainstem]] and [[spinal cord]]. [[Cognition|Cognitive]] and [[volition (psychology)|volitive]] systems project fibers from the cerebrum to the [[thalamus]] and to specific regions of the [[midbrain]]. The neural networks of the cerebrum facilitate complex behaviors such as social interactions, thought, judgement, learning, [[working memory]], and in humans, speech and [[language]].

== Functions ==
'''Note''': As the cerebrum is a gross division with many subdivisions and sub-regions, it is important to state that this section lists the functions that the cerebrum ''as a whole'' serves. See main articles on [[cerebral cortex]] and [[basal ganglia]] for more information.

=== Movement ===
The cerebrum directs the conscious or volitional motor functions of the body. These functions originate within the [[primary motor cortex]] and other frontal lobe motor areas where actions are planned. [[Upper motor neuron]]s in the primary motor cortex send their [[axon]]s to the brainstem and spinal cord to [[synapse]] on the [[lower motor neurons]], which innervate the muscles. Damage to motor areas of cortex can lead to certain types of [[motor neuron disease]]. This kind of damage results in loss of muscular power and precision rather than total [[paralysis]].

=== Sensory processing ===
The primary sensory areas of the [[cerebral cortex]] receive and process visual, auditory, [[somatosensory]], [[gustatory]], and [[olfactory]] information. Together with association cortical areas, these brain regions synthesize sensory information into our perceptions of the world around us.

=== Olfaction ===
{{Main|Olfaction}}
The [[olfactory bulb]] in most vertebrates is the most anterior portion of the cerebrum, and makes up a relatively large proportion of the telencephalon. However, in humans, this part of the brain is much smaller, and lies underneath the frontal lobe. The olfactory sensory system is unique in the sense that neurons in the olfactory bulb send their axons directly to the [[piriform cortex|olfactory cortex]], rather than to the [[thalamus]] first. Damage to the olfactory bulb results in a loss of the sense of smell.

=== Language and communication ===
{{Main|Language}}
[[Speech communication|Speech]] and language are mainly attributed to parts of the cerebral cortex. Motor portions of language are attributed to [[Broca's area]] within the frontal lobe. Speech comprehension is attributed to [[Wernicke's area]], at the temporal-parietal lobe junction. These two regions are interconnected by a large [[white matter]] tract, the [[arcuate fasciculus]]. Damage to the Broca's area results in [[expressive aphasia]] (non-fluent aphasia) while damage to Wernicke's area results in [[receptive aphasia]] (also called fluent aphasia).

=== Learning and memory ===
{{Main|Memory}}
Explicit or declarative (factual) memory formation is attributed to the [[hippocampus]] and associated regions of the medial temporal lobe. This association was originally described after a patient known as [[HM (patient)|HM]] had both his hippocampuses (left and right) surgically removed to treat severe epilepsy. After surgery, HM had [[anterograde amnesia]], or the inability to form new memories.

Implicit or procedural memory, such as complex motor behaviors, involves the basal ganglia.

Short-term or working memory involves association areas of the cortex, especially the [[Neuroanatomy#Orientation in neuroanatomy|dorsal lateral]] part of the [[prefrontal cortex]], as well as the hippocampus.

==Variation among species==
In the most primitive living vertebrates, the [[hagfish]]es and [[lamprey]]s, the cerebrum is a relatively simple structure receiving nerve impulses from the [[olfactory bulb]]. In [[cartilaginous]] and [[lobe-finned fish]]es, and also in [[amphibian]]s, a more complex structure is present, with the cerebrum being divided into three distinct regions. The lowermost (or ventral) region forms the basal nuclei, and contains fibres connecting the rest of the cerebrum to the [[thalamus]]. Above this, and forming the lateral part of the cerebrum, is the ''paleopallium'', while the uppermost (or dorsal) part is referred to as the ''archipallium''. The cerebrum remains largely devoted to olfactory sensation in these animals, despite its much wider range of functions in [[amniote]]s.{{ref|VB}}

In [[ray-finned fish]]es, the structure is somewhat different. The inner surfaces of the lateral and ventral regions of the cerebrum bulge up into the ventricles; these include both the basal nuclei and the various parts of the pallium, and may be complex in structure, especially in [[teleost]]s. The dorsal surface of the cerebrum is membranous, and does not contain any nervous tissue.{{ref|VB}}

In the amniotes, the cerebrum becomes increasingly large and complex. In [[reptile]]s, the paleopallium is much larger than in amphibians, and its growth has pushed the basal nuclei into the central regions of the cerebrum. As in the lower vertebrates, the grey matter is generally located beneath the white matter, but in some reptiles, it spreads out to the surface to form a primitive cortex, especially in the anterior part of the brain.{{ref|VB}}

In [[mammal]]s, this development proceeds further, so that the cortex covers almost the whole of the cerebral hemispheres, especially in more "advanced" species, such as [[primate]]s. The paleopallium is pushed to the ventral surface of the brain, where it becomes the olfactory lobes, while the archipallium becomes rolled over at the medial dorsal edge to form the [[hippocampus]]. In [[placental mammal]]s, a [[corpus callosum]] also develops, further connecting the two hemispheres. The complex convolutions of the cerebral surface are also found only in higher mammals.{{ref|VB}}

The cerebrum of [[bird]]s has evolved along different lines to that of mammals, although they are similarly enlarged, by comparison with reptiles. However, this enlargement is largely due to the basal ganglia, with the other areas remaining relatively primitive in structure. For example, there is no great expansion of the cerebral cortex, as there is in mammals. Instead, an [[High vocal center|HVC]] develops just above the basal ganglia, and this appears to be the area of the bird brain most concerned with learning complex tasks.{{ref|VB}}

== See also==
* [[List of regions in the human brain]]
* [[Cerebral cortex]]
* [[Basal ganglia]]

== References ==
#{{note|VB}} {{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 536–543|isbn= 0-03-910284-X}}

==External links==
* [http://www.rahulgladwin.com/blog/2006/06/cerebrum-higher-integrative-functions.html Cerebrum Medical Notes on rahulgladwin.com]
* [http://www.neuinfo.org/nif/nifgwt.html?query=%22Cerebrum%22 NIF Search - Cerebrum] via the [[Neuroscience Information Framework]]

{{Nervous system}}
{{Cerebral cortex}}
{{Commissural fibers}}
{{Lateral ventricles}}
{{Rostral basal ganglia and associated structures}}
{{Association fibers}}

[[Category:Cerebrum| ]]

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[[eo:Grandcerbo]]
[[fa:مخ]]
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Talk:Lateralization of brain function

2011-09-12T15:03:04Z

PhineasG:

Talk:Lateralization of brain function

2011-09-12T15:01:51Z

PhineasG: /* Connection between Broca's and Wernicke’s */

{{talk header}}
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== Popular meaning ==
Can't the article start with the popular meaning, as a way to debunk it, but still be useful. People every day say "left brained" and I came here to see what it meant and was confronted by a wordy pedantic wordy blah blah wordy yadda yadda wordy digression. Or perhaps just have an article called "left brained" and put in the popular meaning and say "but it ain't true, see lateralization". Wikipedia is getting ruined by amateur pedants.

Disagree. If you want the "popular" meaning based on usage, consult a dictionary. If you want the currently most popular meaning, consult a web-dictionary. Wikipedia strives to be an encyclopedia that indexes and strives toward organization of the knowledgeable, not the knowledge of the man-in-the-street. In any case, there are an almost infinite number of "popular" conceptions about. Which of those do you propose be used? Yours?

==Confusion on lateralization==
I have seen it asserted that scientific research has found that mathematics is done with the left brain. But I wonder whether those whom brain researchers observed "doing mathematics" were doing
* what '''brain researchers''' consider to be "mathematics", or
* what '''mathematicians''' consider to be "mathematics"?
For example, suppose one who has a good handle on the standard first-year calculus course is asked to evaluate the integral
::<math>\int {dx \over (x^2 + 4x + 13)^2}.</math>
I have a deep dark suspicion that some of those brain researchers think that's what mathematics is (it would be a bit like mistaking copy-editing for English literature). On the other hand, suppose a 10-year-old wonders why it is that when you add two odd numbers you get an even number and when you multiply two odd numbers you get an odd number, and figures it out (all 10-year-olds do things like this, except perhaps those who will grow up to be non-mathematicians). That would in fact be mathematics. Likewise, figuring out how to evaluate the integral above without having seen it done in textbooks, as opposed to following the textbook routines, would be mathematics.

So which is it (if either)? [[User:Michael Hardy|Michael Hardy]] 23:05, 27 January 2006 (UTC)

Have a look at [http://scholar.google.com/scholar?hl=en&lr=&q=cache:MHqlXwaDu8YJ:psych.colorado.edu/~dmartich/1001/Singh.pdf+author:%22Singh%22+intitle:%22Interhemispheric+Interaction+During+Global%E2%80%93Local+...%22]
:''These results suggest that enhanced interhemispheric interaction is a unique functional characteristic of the mathematically gifted brain.''
a bit of intensive websearching reaveals a few interesting gems on the subject which I can't remember off hand. I seem to remember finding a study somewhere showing high numbers of left handed in mathematically gifted people.

As you point out there are two different processes going on in mathematics at different levels. There can be intesive symbolic work which fits with the left hemisphere language processing areas. But there is also a more conceptual side possibly requiring right brain processing.

Good to see this article created. I did quite a bit of research on the subject last year and found a whole bunch of interesting stuff have a look at [http://singsurf.org/brain/rightbrain.html].
--[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 23:28, 27 January 2006 (UTC)

::Thank you. [[User:Michael Hardy|Michael Hardy]] 23:58, 27 January 2006 (UTC)

I am being taken to task for suggesting that it is disrespectful to brain researchers who (and I do know this) use sophisticated mathematics, to suggest that in their assertions about which parts of the brain are involved in mathematics, they are applying a childishly simple notion of what mathematics is. But this article as it is now written does encourage that impression. If the impression is wrong, the article should be changed accordingly. [[User:Michael Hardy|Michael Hardy]] 00:00, 28 January 2006 (UTC)
:No one should take you to task; these are important and pertinent points you raise. You may find it useful to look up [[acalculia]]; this is a neurologic finding that can be seen in relative isolation. In clinical practice it refers to difficulty with simple calculation - addition and subtraction, mainly, at least as I have seen it tested. Gerstmann claimed it was related to lesions of the left angular gyrus, but this is probably too specific to be applicable in all cases. -[[User:Ikkyu2|Ikkyu2]] 23:14, 28 January 2006 (UTC)
::Heh. He's referring to [http://en.wikipedia.org/w/index.php?title=User_talk:Michael_Hardy&diff=37013979&oldid=36467040 my comment here] that I left on his user page. As the self-appointed [[Wikipedia:Esperanza|Esperanza]] bouncer I don't take too kindly to perceived intentional rudeness; I am a big fan of the [[Meta:Don't be a dick]] policy. Also, your point on [[acalculia]] (an article I've helped write) is dead on, but still not quite the point Mr. Hardy is getting at methinks. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 23:36, 28 January 2006 (UTC)

:::"Perceived intentional rudeness" was only ''perceived''. Nor do I think there was ''u''nintentional rudeness; someone just misunderstood what I wrote. However, I will admit that if I had written less hastily, I might have anticipated some ways in which my words could get misunderstood and taken care to phrase it differently.

:::"Semiconscious" also seems to think I was "talking at" him, but in fact I have paid close attention to his words. [[User:Michael Hardy|Michael Hardy]] 23:53, 2 February 2006 (UTC)

I'll see if I can add dig up some more references. I'm also concerned about the word '''Reasoning''' in
:''Reasoning functions such as language and mathematics are often lateralized to the left hemisphere of the brain''
from my understanding its more symbolic processing and temporal processing in the left. Reasoning is a little to broad a claim. --[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 00:30, 28 January 2006 (UTC)
::[[User:Pfafrich|Salix alba]]: If you would not mind altering this as well, I would appreciate it. I'm trying to simultaneously do too many real life things to really correct this language right now. See my response below for my thoughts on this article. If you don't get to this in the next few days I should have time next week to dig up better references and resources to more clearly express the notion of laterality of "reasoning" in the brain. Cheers! [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 19:04, 28 January 2006 (UTC)
::: No problem I'll wait. This seem an article very much in gestation at the moment. --[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 19:11, 28 January 2006 (UTC)

== New Scientist 28 Jan 06 ==
Interesting series of articles in this week New Scientist in particular ''Glad to be Gullible'' by ''Clare Wilson''. [http://www.newscientist.com/channel/being-human/mg18925361.300.html].

A few relevant quotes:
*''What determins our tendancy to spot patterns and form associations? It turns out that the key factor is the relative dominance of the right and left hemispheres of the brain. ... Most neuroscientists would accept that the left side of the brain is primarily responsable for language and logical analysis, while the right side is more involved in creativity and what might be called lateral thinking - making connections between disprate concepts''.
*''Several recient studies suggest that people who beleive in the paranomal have greater right brain dominance'' (See Psychiatry Research:Neuorimaging, vol 100, p139 and Psychopathology, vol 34, p75).
*''Brugger and other have shown that there is relativly more right brain activity in people with schizophrenia''

[http://www.neuroscience.unizh.ch/e/groups/brugger00.htm Peter Bruger] a neroscientist at University Hospital, Zurich. Seems a man to watch. --[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 15:25, 27 January 2006 (UTC)

==Long-winded reply==
We are treading dangerously close to semantics here based upon hearsay rather than fact, so I am going to preface this by providing a definition of ''mathematics'' from [http://www.dictionary.com dictionary.com] to ensure we all begin from the same point:
math•e•mat•ics
n. (used with a sing. verb)
# The study of the measurement, properties, and relationships of quantities and sets, using numbers and symbols.
# a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement [syn: math, maths]
[[User:Michael_Hardy] provides one of these two definitions and seems to assign one of them more correctness than the other based upon a non-defined, unreferenced claim of a "mathematicians definition". In fact this notion is furthermore brought forth in Wikipedia's own entry on [[Mathematics]] which suggests (without citing any sources) that ''Another view, held by many mathematicians, is that mathematics is the body of knowledge justified by deductive reasoning, starting from axioms and definitions''. Stating that “many people” hold any particular definition of something is extremely vague and potentially unfounded and inaccurate , but I'll run with it.

[http://www.sciencemag.org/cgi/content/full/284/5416/970 This article from ''Science'' magazine] attempts to describe more precise definitions of "mathematics", suggesting it either has linguistic origins or is more visuo-spatial. The crux of the article suggests there are different forms, what they call "exact arithmetic" and "approximate arithmetic". "Exact arithmetic"--"what brain researchers consider to be mathematics'"--is strongly left-lateralized as this article suggests. "Approximate arithmetic"--"what mathematicians consider to be 'mathematics'"--is bilateral.

Again, in deference to civility, I will amend this article to more clearly state these differences despite my intuition that this is a semantic argument that is unnecessarily clouding what is essentially an already poorly-defined notion. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 00:29, 28 January 2006 (UTC)

::Also, thank you both for coming here to edit this page: if nothing else it is enforcing a more precise definition of the terms we are using. If I am coming across as abrasive, I have no intentions other than clarity and I truly appreciate the efforts here. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 00:37, 28 January 2006 (UTC)

I was not suggesting anything about "approximate" versus "exact". I was suggesting that

* using mathematical methods developed by others in more-or-less mechanical fashion

involves a different kind of thinking from

* actually developing such methods from scratch, regardless of whether that is done by a mathematician breaking new ground or a fourth-grader figuring out without help why it is that when you multiply two odd numbers you always get an odd number, or figuring out, without having heard it asserted by teachers or textbooks or anyone else, that the sum of the angles of a triangle is always 180 degrees.

Those are two different kinds of thinking. The latter is not "approximate". [[User:Michael Hardy|Michael Hardy]] 00:55, 28 January 2006 (UTC)

::What I seem to be poorly expressing here is that--while I understand your point—it is too ill-defined for an encyclopedic article. You have pointed out to me a place where the language is poorly defined and thus open to many interpretations. Therefore I have altered the language acordingly and provided a citation in support of my change. You can continue arguing about your feelings as to what "mathematics" truly is but that is no longer relevant to this article or this discussion as the word "mathematics" or any of its variants no longer appears in the article in any form (other than in the title of reference I provided).
::I further agree with [[User:Pfafrich|Salix alba]] that "reasoning" is a poor word choice as well. In my experience, the casual reader on Wikipedia does not like a great deal of technical language. In my attempt at trying to communicate a relatively simple idea to benefit the maximum number of readers, I chose to use simpler terms. This was clearly not an appropriate choice however, as I was unaware at how poorly defined a term such as "mathematics" was. My point being, you may continue arguing this--and I will gladly engage you in an argument of semantics if you would like--however in the context of this article I consider this issue to be resolved. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 19:01, 28 January 2006 (UTC)

:::I don't think imprecision in the definition of "mathematics" is the issue here at all. It is not easy to define "mathematics", and any definition would be subject to endless debate among informed people (and uninformed ones too, I suppose). But I meant that what actual mathematicians and other actual humans actually do, when doing things that everyone would agree is mathematics, is mostly not algorithmic processing. [[User:Michael Hardy|Michael Hardy]] 01:03, 30 January 2006 (UTC)

A distinction I've always like is betwene Algebra and Geometry. Mathematics can been seen as a process of expressing Geometry in Algebra. Loosly it could be said algebra happens on the left and geometry in the right. (unverified!) --[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 00:57, 28 January 2006 (UTC)

::No -- I don't think so. Algorithmic processing versus creative thinking about mathematics is closer to what I had in mind. The latter is what mathematicians are trying to do; the former is a means. [[User:Michael Hardy|Michael Hardy]] 01:00, 30 January 2006 (UTC)

==Exact/algorithmic/blah blah==
Hardy: Did you read the citation I provided? I was simply using the language they used. You can apply whatever words you'd like to this: it's so nebulously defined that I just really don't care. However I find you use of the phrase "recent discussion tends to confirm my suspicion" in your edit summary amusing, since it was more you talking ''at'' me rather than a discussion. :) [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 00:11, 1 February 2006 (UTC)

::I've looked at it enough to know that it provides some context that aids in understanding what they mean by "exact arithmetic" and that context is not (yet, anyway) in the present Wikipedia article. That article ''and'' the things you and others have said here do tend to confirm my suspicion. It's just as if they were confusing that sort of thinking with what mathematics actually is. [[User:Michael Hardy|Michael Hardy]] 21:26, 1 February 2006 (UTC)

== A cap on discussion ==
Recall that we are editing an assemblage of other people's work here, not conducting original research or trying to form cohesive theories out of disparate publications. Much of the current discussion above would absolutely vanish if the editors would confine themselves to statements developed from and taken directly from source publications, ideally cited by page number and possibly quoted briefly under fair use. -[[User:Ikkyu2|Ikkyu2]] 19:48, 1 February 2006 (UTC)
:Ugh I'm so sick of this. Michael Hardy clearly has strong feelings a '''''his''''' definition of math. After looking over at the [[Mathematics]] article, there's a huge issue with defining mathematis; I'm not sure why Michael Hardy is coming in here and making changes that go against a cited article in ''Science'' inserting his own definition based upon phrases such as "confirm my suspicion" and "what mathematics actually is". These are opinions sir, and not worthy of countering a good citation. I have conceded several times over that my original statement was unclear, so I feel the citation is a good compromise. But you just keep inserting your own personal views on the matter.
:It's [http://en.wikipedia.org/w/index.php?title=Mathematics&diff=11180862&oldid=11180822 clear] you feel strongly on this matter, but others [http://en.wikipedia.org/w/index.php?title=Talk:Mathematics&diff=11160991&oldid=11160652 feel differently] than you and [http://en.wikipedia.org/wiki/Talk:Mathematics#NPOV_and_original_research.3F defining mathematics] is [http://en.wikipedia.org/wiki/Talk:Mathematics#Recent_revert_wars problematic], so please quit reverting based upon your suspicions. Suspicion does not trump citation. [[User:Semiconscious|S]][[Wikipedia:Esperanza|e]][[User:Semiconscious|miconscious]] • [[User talk:Semiconscious|talk]] 02:15, 2 February 2006 (UTC)
:::I did not propose any particular definition of mathematics. I don't know why Semiconscious thinks I did. I edited this article for clarity, not to support particular opinions. The only thing I said about the nature of mathematics consisted of a list of '''examples''', not a definition, and I don't think any of them are controversial. Also, to say that mechanically executing algorithms is '''not''' mathematics is also not contrvoersial. [[User:Michael Hardy|Michael Hardy]] 00:03, 16 February 2006 (UTC)

== Recent Brain Research: Fascinating Implications for Educators ==
Found a facinating review of litrature on brain research:
''Recent Brain Research for Teachers & Other Curious Souls''
By Wenda Sheard, J.D., Ph.D. [www.hoagiesgifted.org/Recent%20Brain%20Research.ppt]

Some of the finding include:
*O’Boyle, M. W., Alexander, J. E., & Benbow, C. P. (1991). Enhanced right hemisphere activation in the mathematically precocious: a preliminary EEG investigation. Brain and Cognition, 17(2): 138-153. EEG patterns of LH activation differ in mathematically precocious youth from that of average math ability students. “Enhanced RH involvement during cognitive processing may be a correlate of mathematically precocity.” Three tasks: gaze at blank slide, judge which of two faces was happier, determine if a word is a noun or verb. (EEG, Six mathematically precocious youth mean age 13.2 SAT-Math mean 670, all right-handed, 10-item questionnaire about which hand used when performing tasks. Control group of 8 right-handed males not precocious at math. Eight EEG sites with cap.)
*Raz, N., Torres, I. J., Spencer, W. D., & Millman, D. (1993). Neuroanatomical correlates of age-sensitive and age- invariant cognitive abilities: An in vivo MRI investigation. Intelligence, 17: 407-422. MRI, brain symmetry, 29 subjects ages 18-78. “The magnitude of leftward hemispheric volume asymmetry significantly and uniquely contributed to explaining the variance in both cognitive measures (non-verbal reasoning and vocabulary).
*Alexander, J. E., O’Boyle, M. W., & Benbow, C. P. (1996). Developmentally advanced EEG alpha power in gifted male and female adolescents. International Journal of Psychophysiology, 23(1-2): 25-31. EEG study of 30 gifted adolescents (mean age 13.3, SAT averages 1100), 30 average ability adolescents, and 30 college-age subjects. “(T)here were no significant differences in overall alpha power between college-aged and gifted adolescent subjects. These finding suggest that gifted adolescents may have a developmentally enhanced state of brain activity, one that more closely resembles that of college-age adults to whom they also resemble in terms of cognitive ability.”
*Jausovec, N. (1997). Differences in EEG alpha activity between gifted and non-identified individuals: Insights into problem solving. Gifted Child Quarterly, 41: 26-32. EEG. Seventeen gifted (IQ over 130 WISC, 3 male & 17 female) and 17 non-identified solved four problems. Recorded relaxed and problem-solving mental states, and hemispheric symmetry/asymmetry. Gifted more LH (Left Hemisphere activity) when in relaxed state. Non-identified more LH when in problem-solving state.

--[[User:Pfafrich|Salix alba]] ([[User talk:Pfafrich|talk]]) 18:48, 15 February 2006 (UTC)

== Split-brain patients: separate article? ==
I think the section "Split-brain patients" warrants an article. Thoughts?

== Lateralization - help request ==
I've been given a rough time by someone arguing that some authors say brain lateralization is an old concept. Is that so, or not?

I need to know the current state of belief about brain lateralization, and how sure or accepted it is in neuroscience/cognitive science, with a few more cites or findings.

If there was a controversy or dispute, but it's no longer in question, or it's been clarified, could a section "Controversy" be added to the article to make it clearer?

Last, I've tidied up the references as a way to say thankyou in advance for any help. The footnote from "Goulven" isn't referenced in the article, someone needs to fix it :)

Many thanks!

[[user:FT2|FT2]] ([[User_talk:FT2|Talk]] | [[Special:Emailuser/FT2|email]]) 11:43, 30 June 2006 (UTC)

:Like most science the answers tend not to be cut and dried. The field it is still very much a work in progress and as functional imaging techniques improve we will begin to learn more about how verious functions are localised in the brian. Its worth reading the rest of this talk page where there are quite a few references which haven't made it into the main article. Alas I have several other projects on the go so I don't have much time to devote to this article. If you can get hold of Goulven it might provide a good summary of recient research. --[[User:Salix alba|Salix alba]] ([[User talk:Salix alba|talk]]) 14:48, 30 June 2006 (UTC)
::But is the principle of higher cognitive functions being lateralized, pretty much established, or still disputed, or disproven? [[user:FT2|FT2]] ([[User_talk:FT2|Talk]] | [[Special:Emailuser/FT2|email]]) 16:19, 30 June 2006 (UTC)

:::It depends on the function. I think you are referring to popular ideas of left and right. Sure there is a lot of nonsense spread by marketeers of various products. Early in the 70s it was left and right brain people, then later people talked about getting a balance by various means (certain machines, drugs, activities). Some old psychology techniques used the left right brain research of early neuroscience. They made all sorts of unfounded claims for methods. I think this could be added into a section. I have a book on popular myths. It may be useful to open a section. I will add something provisionally using the information. Please revert it if you think it is wrong. [[User:Pacificsun|Pacificsun]] 03:18, 19 July 2006 (UTC)

==Lateralization in pop psych and as extended to cultural metaphors?==
I came to this article looking for a critical discussion of the left-brain/right-brain concept as it is misapplied by non-academics (as well, perhaps, as by some people with enough training in psychology to know better). It's common to the point of cliche to say, usually without any scientific evidence, that a particular activity, organization, job, or even a whole person or society is "left brain" or "right brain". I think that this article would benefit by a section or perhaps an external supplemental article on this question.

Here's a citation which gives some examples of what I'm talking about, although it is from the management literature and may be slightly off-target for this article:

Hines, Terence (1987). Left Brain/Right Brain Mythology and Implications for Management and Training. The Academy of Management Review, 12:4, 600-606.

:Excellent call - yes please! Seconded. Some expert....? :) [[user:FT2|FT2]] ([[User_talk:FT2|Talk]] | [[Special:Emailuser/FT2|email]]) 23:24, 2 July 2006 (UTC)

I looked it up and it is good information. I also have other citations to add to the section. I added also the pseudoscience category. This is a category that helps readers browse any articles with pseudoscience issues. Its not a list of pseudosciences and it doesn't mean that lateralization of brain functioning is pseudoscience. Have a good weekend [[User:Matlee|Matlee]] 06:36, 25 August 2006 (UTC)

== copied section ==
:''In a test in which split- brain patients had to match a series of household objects, the left brain would match by function while the right would match by appearance. So, when seeing a cake on a plate, the left brain would connect to a picture of a fork and spoon while the right brain would select a picture of a broad-brimmed hat. This evidence appeared to support the idea of a highly modular brain in which, for example, thinking in logical categories was a strictly left hemisphere function while mental imagery and spatial awareness were handled on the right''

:''But, says Joseph Hellige, a psychologist at the University of Southern California, this picture changed dramatically as soon as brain-scanning experiments began to show that both sides of the brain played an active role in such processes. Rather, it seemed to be processing styles that distinguished the two halves. Under the scanner, [[language]] turned out to be represented on both sides of the brain, in matching areas of the cortex. Areas on the left dealt with the core aspects of speech such as [[grammar]] and [[word]] production, while aspects such as [[Intonation (linguistics)|intonation]] and [[emphasis]] lit up the right side. In the same way, the right brain proved to be good at working with a general sense of space, while equivalent areas in the left brain fired when someone thought about objects at particular locations.''

Copied from http://www.rense.com/general2/rb.htm --[[User:Tgr|Tgr]] 09:09, 10 December 2006 (UTC)

== InternetHero's edits ==
[[User:InternetHero]] keeps adding the phrase "science of math" to the list of things allegedly done by the left brain. Simple arithmetical calculations are not science. Mathematics, on the other hand, is by some reasonable definitions, science.

In 3rd grade you're told that 5 × 3 is

: 3 + 3 + 3 + 3 + 3

whereas 3 × 5 is

:5 + 5 + 5.

You're '''also''' told that not only do those yield the same number, but that that holds generally, with any other numbers.

If you figure out why that pattern holds generally, you're doing mathematics. But if you develop calculation skills without understanding such things, you're '''not''' doing mathematics, let alone "science of mathematics". [[User:Michael Hardy|Michael Hardy]] 20:45, 19 February 2007 (UTC)

:The concept of multiplication. Do you understand the brain or just math? Please answer honestly.

:Again, I think zinc ions are relevent here. I really don't understand the sloppiness and disregard for basic courtesy in your edits. I will revert from editing untill properly designated, but seriously for almost everyone except overly reformative mathematicians, the ability of arithmetic is in strong relation to math.

:Also, are you denying Benjamin Peirce's words: "the science that draws necessary conclusions". [[User:InternetHero|InternetHero]]--23:31, 27 March 2007 (UTC)

Please see science. Hi, sorry for not discussing with you 1st, but I didn't know you could.

The broadness of science and it's many sub-catogories derived from it's autonomity/abstractness, were meant to be pertained in respect to the concepts of contrast and/or comparison. As you state, the reasonable/logical properties of mathematics can be attributed to both sides of the corpus.

I've made myself a folly. I got 2 attached and let my perogatives take over my reasoning in respect to putting science in both charts. I got attached to this because of the other edit which entitled: Science of Math - Science of Philosophy.

As Michael pointed out, both sides can bi-laterally comprehend mathematical concepts. I was wrong.

Science can constitute any system of objective knowledge - which in this case, refers to the 'system' of simple-algoritmic proccesses via the system of transducing of stimuli.

1) "simple computations are not "science"; 2) mathematics does not consist of simple algorithmic processing"

i) Wiki - Scientific Method: It is based on gathering observable, empirical, measurable evidence, subject to the principles of reasoning.

ii) Wiki - Mathematics: Is the body of knowledge centered on concepts such as '''quantity, structure, space, and change''', and also the academic discipline that studies them.

When savants draw a picture of a buildings window patterns, they can't process concepts like Base x Height. The can individually count or 'grasp' all the windows as a whole, and draw them in that respect. If this process is not a matter of the concepts bolded above, then I don't know what is. [[63.135.9.214]]/[[InternetHero]] 05:01, 19 February (UTC)

==Semantic and Episodic memory==
They both are used my the temporal lobe also:

''"The medial temporal lobes (near the Sagittal plane that divides left and right cerebral hemispheres) are thought to be involved in '''episodic/declarative memory'''. Deep inside the medial temporal lobes, the hippocampi seem to be particularly important for memory function - particularly transference from short to long term memory and control of spatial memory and behavior."'' [http://www.sci.uidaho.edu/med532/temporal.htm]

You guys make a conclusion for yourselves, but I think theres something here. For instance, it states above that the Sagittal plane involves episodic memory, yet is involved in semantic memory as a pre-requisite of declarative memory (Declarative: Semantic/Episodic).

[http://en.wikipedia.org/wiki/Declarative_memory]

This can also be related to left-handed people and this article:

''"In 2006, researchers at Lafayette College and Johns Hopkins University in a study found that left-handed men are 15% richer than right-handed men for those who attended college, and 26% richer if they graduated. The wage difference is still unexplainable and does not appear to apply to women.[26]

As well as possible intelligence advantages, being left-handed can also bring about other benefits, including:

Brain hemisphere division of labor: The premise of this theory is that since both speaking and handiwork require fine motor skills, having one hemisphere of the brain do both would be more efficient than having it divided up.[citation needed]
Advantage in hand-to-hand combat: Left-handers have a 'surprise' factor in combat, since the majority of the population is right-handed."'' [http://en.wikipedia.org/wiki/Left-handed]
- [[User:InternetHero]] 17:33, 16 April, 2007 (UTC)

== Pseudoscience category? ==

:Hines (1987) states that the research on brain lateralization is valid as a research program, though it has been applied to promote subjects and products far out of the implications of the research. For example, the implications of the research have no bearing on psychological interventions such as [[EMDR]], brain training equipment, or management training. One explanation for being so prone to exaggeration and false application is that the left-right brain dichotomy is an easy-to-understand notion, yet is often grossly oversimplified and misused for promotion in the guise of science. This is often known as right-brain mythology, and is associated with occult notions such as yin/yang, righteous and sinister, and day and night. The research on lateralization of brain functioning is ongoing, and its implications are always tightly delineated, whereas the pseudoscientific applications are exaggerated, and applied to an extremely wide range of situations. Hines, Terence (1987). Left Brain/Right Brain Mythology and Implications for Management and Training. The Academy of Management Review, 12:4, 600–606.

:I moved the above section here for discussion. I don't think this article should be in the pseudoscience category. I have removed it. But wanted to open a discussion here and past this paragraph that I cut from the article. Is this really necessary? --[[User:Comaze|Comaze]] 15:12, 26 June 2007 (UTC)

::I think that it's important that such material be here, given that there is a popular misconception about the "left-brain/right-brain" sort of research. There is clearly a real, and proper scientific research program going on regarding the relative strengths and capacities of the cerbral hemispheres (i.e., left for language production, dating back to Broca, or the preponderance of right sided lesions leading to neglect) which serious cognitive neuroscientists recognize as part of their domain. However, that research has largely caught the attention of the general public in a watered down, distorted manner, and I think that it is important to mention this not as a piece of congitive neuroscience, but as a piece of sociology of how scientific findings are dissemenated and used by the general public. I agree, however, that laterlazation of brain function is not pseudoscience, and agree that the cat should be removed. [[User:Edhubbard|Edhubbard]] 00:35, 27 June 2007 (UTC)

:::I think the text needs to be summarised and put in the main body somewhere. We do need to be careful because most functions that are popularly thought of as lateralised are present in both sides of the brain. However, in general the left-hemisphere tends to be dominant for logic, language whereas the right hemishpere tends to be dominant for non-linguistic functions (visualisation, mental rotation, face recognition, etc.)(p.7 ''Western et al. 2006 "Psychology: Austraian and New Zealand edition" John Wiley''). So the popular understanding is not too far off the mark. --[[User:Comaze|Comaze]] 04:56, 27 June 2007 (UTC)

The reference of Hines definitely says its used in a pseudoscientific way if too broad. I will have a look at the rules for inclusion to the pseudoscience category though. I am working in neuroscience research and there is a big complaint by neuroscientists about people saying pseudoscientific things about hemisphericity. Its big issue and is taught at university level. So neuroscientists and science thinkers like Hines want to say that there is a big pseudoscience problem here in this small area of hemisphericity because of commercial persuasion. But they do not say there is a pseudoscience problem generally in neuroscience. [[User:Matlee|Matlee]] 05:57, 27 June 2007 (UTC)

:I can understand why you want to warn people about the mythology in brain sidedness. There are people running around saying that people are more left or right brained, etc. However, I'm not convinced that this article should be in the pseudoscience category. Nor am I convinced of the reliability or authority of Hines as a source for this article. Besides, the main issues are covered in the lead. It now says something like the popular lateralised functions are actually located on both sides of the brain. --[[User:Comaze|Comaze]] 06:33, 27 June 2007 (UTC) Perhaps we could have paragraph covering the left-right sidedness myths with appropriate evidence. --[[User:Comaze|Comaze]] 06:41, 27 June 2007 (UTC)

::Ok I'll look for more sources but I think the Academy Management Review is good enough. I kept some references from a seminar I went to on this problem and will check them. There were also some more commercial examples who use the pseudoscience ideas listed. I might have a look on the web because I am sure its a getting more popular problem. Do you know of any other area that might use myths? I have some idea but not sure about the sort of range. [[User:Matlee|Matlee]] 06:49, 27 June 2007 (UTC)

:::Thanks. These left/right brain myths pop up in teaching, adult education and management training. Best --[[User:Comaze|Comaze]] 07:19, 27 June 2007 (UTC)

:::I think there are two seperate issues here. One is the category tag, which I should stay removed (good spot Comaze), since it seems to apply to the whole article, while it is only this one section that is ''potentially'' pseudoscientific. As I noted above, there is some scientific truth to the idea that the hemispheres do slightly different things, but that has been '''radically''' oversimplified, to the point of potential misrepresentation in the eyes of the generral public. I think Matlee is right to emphasize the word '''dominant''', which is exactly what is missing from much of the pop-culture discussions of lateralization of brain function. As for the actual content, I think that we should probably use more up-to-date and more cognitive neuroscience references, of which I can suggest three good ones here off the top of my head:
:::*J. Graham Beaumont (1983). ''Introduction to Neuropsychology.'' The Guilford Press. ISBN 0898625157. - This book is a bit dated (he is working on an updated version) but his discussion of the link between lesions of the left or right hemisphere, language and handedness is some of the most detailed and complete in the textbook world.
:::* Michael S. Gazzaniga, Richard B. Ivry, George R. Mangun (2002). ''Cognitive Neuroscience, Second Edition.'' W. W. Norton & Company ISBN 0393977773. - This is the textbook that we used when I was an undergraduate, and will be one of the two texts that I will use (along with Ramachandran's ''Phantoms in the Brain'') when I teach my own class. It includes a seperate chapter on lateralization of brain function (Ch. 9), but also treats lateralization in the appropriate places, along with the relevant topics. They are currently working on a third edition. Note, also that Ivry and Robertson have a more integrated account of how such differences might arise from low-level differences in the spatial and temporal frequencies preferentially treated by the two hemispheres (''The Two Sides of Perception'', 1997 MIT Press) although this is probably beyond the scope of the current article. Also, of course, there is a thorough treatment of split-brain work here, given that Gazzaniga is first author.
:::*Jamie Ward (2006). ''The Student's Guide to Cognitive Neuroscience.'' Psychology Press. 1841695343. The most recent cognitive neuroscience textbook on the market, and one that is unique in that, it is the only one (so far) to have chapters on topics like the cognitive neuroscience of reading and numerical cognition (Chs. 11 and 12, respectively). It also tends to place more emphasis on neuropsychological methods than does the Gazzaniga text (which is why I would supplement Gazzaniga with Ramachandran). Again, there's no separate chapter on lateralizaition of function, but the lateralizations of these functions are treated within the appropriate contexts.
::: The important thing to me is that we, in some way, point out this more subtle point. One hemisphere or the other can be dominant for a given function, this varies by handedness, by sex, etc, but at the same time, there is a lot of this type of stuff that has been radically oversimplified in the public literature, since the earliest discoveries of some of these divisions of labor in the human brain. [[User:Edhubbard|Edhubbard]] 07:28, 27 June 2007 (UTC)

Inferior, terrible, dumb? I don't understand how the evaluative words can be used in the overall category. [[User:72.189.94.109|72.189.94.109]]gurbinav

== external links ==

 
One of the current external links on the site:

* [http://www.everux.com/ura/lbrain_or_rbrain.html Left Brain/Right Brain Visual Aptitude Test]

links to an adult site. From my brief check, the site only has this one page on lateralization as it pertains to this article. While it's an interesting graphic, and it has something to do with left and right as concepts, I don't see any reason for its inclusion in this article. Its claim to be a diagnostic tool for determining left/right dominance ("If [you see the image turning] clockwise, then you use more of the right side of the brain and vice versa."), is unsupported AFAIK. I will remove it if there are no objections. [[User:Aaron.michels|Aaron.michels]] ([[User talk:Aaron.michels|talk]]) 19:00, 16 April 2008 (UTC)
:This is a pretty clear case of an inappropriate external link. Feel free to remove this and any other clear violations. --[[User:Gimme danger|Gimme danger]] ([[User talk:Gimme danger|talk]]) 23:31, 16 April 2008 (UTC)

==Mathematics==

Singular concepts of relativity such as counting (not division where a placeholder is needed) would allow the ions/synaptic plasticity to require certain regions of the brain to be used as a prerequite '''in''' the left brain. It all depends on which part of the brain the person uses, but I'm pretty sure the Corpus is the divisor/placeholder so most of the counting/multiplying wouldn't occur there. You might be able to count holistically like [[savant]]s, but I'm useless in that department as I am not a scientist conducting experiments. [[User:InternetHero|InternetHero]] ([[User talk:InternetHero|talk]]) 02:01, 30 June 2008 (UTC)

I've reverted certain of InternetHero's revisions, sorry, as Dehaene ''et al.'' does not address sidedness of counting, measurement, or perception of shapes or motions. Is there a reason the table lists "perception of counting/measurement" as opposed to simply "counting/measurement"? —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Grothmag|Grothmag]] ([[User talk:Grothmag|talk]] • [[Special:Contributions/Grothmag|contribs]]) 22:26, 1 July 2008 (UTC) 
:The problem really isn't the citations; as they are perfectly reasonable for discussing lateralization of mathematics, but rather the qualifiers of "perception of counting/measurement". I've reinstated the refernces, and put in more precise qualifiers, since at least certain aspects of mathematics ("direct retrieval" as we do with times tables) do appear to be uniquely left-hemisphere lateralized, while other aspects of mathematics, including approximate calculation, comparison and so on, appear to depend on both the left and the right hemisphere. Incidentally, although Dehaene's research does not directly address "perception of shapes or motions [sic]" there is plenty of evidence that demonstrates that visual processing of these features is indeed bilateral (see for example, MT/V5 for processing of motion and LOC for shape). [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 02:17, 2 July 2008 (UTC)

== discrepancy - table/text ==
I just wanted to repeat a remark I made in the ''Cerebral hemisphere'' talk page ([[Talk:Cerebral_hemisphere#table_is_too_general?]]), because it also applies to this article. There is a discrepancy in the presentation: On the one hand it is claimed that popular psychology overemphasizes the lateralization of broadly defined concepts such as logic and intuition, on the other hand the upper half of the table in the section "Which side?" is doing just the same. --[[Special:Contributions/88.72.195.165|88.72.195.165]] ([[User talk:88.72.195.165|talk]]) 17:13, 8 July 2008 (UTC)
: Agreed. And the references are from similar non-reliable sources. I think an expert opinion is required, perhaps a neurologist. The table has no place in an article about the verifyable neuroscience anatomy of the brain, it is decidedly outof place. Perhaps the table should be moved into a separate article about popular neuroscience myths. --- [[User:Roidroid|Roidroid]] ([[User talk:Roidroid|talk]]) 13:50, 27 August 2009 (UTC)
:: Hang on... The discrepancy between the "pop-science" lateralization story and the peer-reviewed [[cognitive neuroscience]] understanding of lateralization is a little more subtle than either of you seem to understand. In short, the problem is not that the hemispheres specialize for certain things, which is supported by a host of evidence, going back over 100 years, but rather that this fact has somehow been translated into the idea that there are "left-hemisphere" people and "right-hemisphere" people. This radical oversimplification of the real evidence from neurology and cognitive neuroscience is what is at issue in several places throughout wikipedia. But, the basic information in the table does not fall prey to that oversimplification. Additionally, Roidroid suggests that the references are non-reliable, but from what I can see, the majority of the references in the article and in the table come from peer-reviewed journals, such as ''Science'' (reference 10), ''Cognitive Neuropsychology'' (reference 11), ''Brain'' (reference 16), and textbooks like ''Psycholinguistics: Learning and using Language'' (reference 15) and ''Principles of Neural Science'' (reference 16). I would agree that the first three lines of the table have to go, but not the entire table. I have removed them, and as such, I am removing the pseduoscience tag. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 12:55, 28 August 2009 (UTC)
::: This seems good now [[User:Roidroid|Roidroid]] ([[User talk:Roidroid|talk]]) 05:25, 21 September 2009 (UTC)

::::I was mainly concerned with the removed parts of the table. As far as I understand it the case for lateralization of verbal processing is strong. Numerical processing possibly but I don't know about that. --[[Special:Contributions/88.74.56.40|88.74.56.40]] ([[User talk:88.74.56.40|talk]]) 21:04, 30 September 2009 (UTC)

== Mathematics ==

Under "left", we find:
:
: mathematics (exact calculation, numerical comparison, estimation)
:
and under "right", we find:
:
: mathematics (approximate calculation, numerical comparison, estimation).
:
Obviously this excludes most of mathematics. Calculation, estimation, and comparison are only a tiny tiny part of all of mathematics. Can more be said, or is that unknown? [[User:Michael Hardy|Michael Hardy]] ([[User talk:Michael Hardy|talk]]) 01:57, 25 October 2008 (UTC)

:Maybe "arithmetic" would be better than "mathematics" here. Unfortunately, I'm not familiar with the sources that are cited for that entry in the table. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 05:53, 25 October 2008 (UTC)
::Yes, I agree that arithmetic would be better than mathematics. In fact, the truth of the matter is that there have been very few studies of anything "higher-level" than basic addition, subtraction and multiplication. The only lab that has taken on even basic algrebra is John Anderson at Carnegie Mellon University. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 04:38, 27 October 2008 (UTC)

OK, a favorite example of mine from "arithmetic":
:
: 3 × 5 means 5 + 5 + 5;
: 5 × 3 means 3 + 3 + 3 + 3 + 3.
:
: '''Why must these two ''differently'' defined things always be the ''same'' number, not only with this particular pair of numbers, 3 and 5, but also with any other pair?'''
:
It's not too hard to answer that question. And it's not too hard to ask that question, when, in childhood, one first learns the definitions. Any child who is curious about math is likely to ask that question, and with a bit more effort to answer it. Now when one thinks it through and figures out what the answer is, then what one is doing is '''mathematics''', and by some definitions, is '''arithmetic'''. But it is '''not''' numerical computation; of either an exact kind or an approximate kind. You don't need to ask about more advanced mathematics than that to see the issue here. The right word for what the article talks about is neither "mathematics" nor "arithmetic"; it is "numerical computation" or "calculation" or the like. [[User:Michael Hardy|Michael Hardy]] ([[User talk:Michael Hardy|talk]]) 03:32, 29 October 2008 (UTC)
:Are you talking about this Wikipedia article or about the Dehaene papers that are being referenced? Anyway, I sort of see what you are saying, but I don't think it's necessarily safe to assume that the brain makes the same distinctions that seem correct philosophically. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 05:01, 29 October 2008 (UTC)
::I think that Michael is referring to the word choice, by pointing out that even what we would typically include under the heading of "aritmetic" is much more complex than what has been done in most imaging studies, due to the technical limitations of the method. So, perhaps something like "calculation" rather than "mathematics"?
::On the scientific point, the closest thing to the type of analysis that Michael is thinking of is work that has been done by John Anderson's group at CMU, where they looked at multidigit multiplication and tested so-called "novice" (right-to-left) computation and "expert" (left-to-right) computation (presented as a poster at last year's Cognitive Neurosocience Society meeting in SF, not yet peer-reviewed to my knowledge). This jumps even beyond the level of analysis Michael is thinking of, but I don't think the exact question he is asking has been addressed using any techniques that allow us to infer lateralization. The general inference is that these simpler tasks, like those used by Dehaene or Brian Butterworth's work in patients, allow us to infer what the substrates of more complex processes may be, but this is an inference. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 14:08, 29 October 2008 (UTC)
:::Actually, going back to Michael's initial point, maybe the best thing would be to call this "numerical cognition"? In that case, we make it clear that we are referring to basic numerical processes, since things like comparison and estimation (that is, estimating the number of objects visually seen, not approximate calculation, which is listed seperately) do not even really rise to the level of "computation". [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 14:11, 29 October 2008 (UTC)

== mentioned in A Scanner Darkly movie and book ==

popculture sub heading

(side note: I am reading a lot of left hemisphere shatter and you guys need to chill and enter the world of the right hemisphere.Grays upon grays.) —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/137.186.195.16|137.186.195.16]] ([[User talk:137.186.195.16|talk]]) 11:16, 1 January 2009 (UTC) 

== Merge with Cerebral Hemispheric Dominance ==

It has been suggested that the article [[Cerebral Hemispheric Dominance]] be merged with this one. I personally dont agree. Dominance and Lateralization are 2 completely different topics.[[User:Em3ryguy|just-emery]] ([[User talk:Em3ryguy|talk]]) 18:46, 1 June 2009 (UTC)

Definitely maintain the separation. Where to put the dominance article without getting into the pseudoscience/ pop-psych debate further would be hard to establish. —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/163.238.46.58|163.238.46.58]] ([[User talk:163.238.46.58|talk]]) 18:03, 12 August 2009 (UTC) 
: In fact, just a quick look at the cerebral hemispheric dominance article suggests that it is a collection of the worst pop-psych misinformation about the cerebral hemispheres around (the whole basic idea that there are "left-brained" and "right-brained" people being the biggest one), contributed almost exclusively by one editor in the course of two days. I don't think that article should be merged with this one, and in fact, think that the article, although having some [[WP:RS|reliable sources]] should probably be deleted, or massively re-written to get rid of the pop-psych "neuromyths" [http://www.oecd.org/document/63/0,3343,en_2649_35845581_34555007_1_1_1_1,00.html] [http://www.psychology.heacademy.ac.uk/plat2006/assets/presentations/Goswami/GoswamiNRN2006.pdf] [http://clive-shepherd.blogspot.com/2007/06/neuromyths.html][http://www.eric.ed.gov/ERICWebPortal/custom/portlets/recordDetails/detailmini.jsp?_nfpb=true&_&ERICExtSearch_SearchValue_0=EJ210602&ERICExtSearch_SearchType_0=no&accno=EJ210602]. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 19:00, 12 August 2009 (UTC)
::I don't actually see any valid content in [[Cerebral Hemispheric Dominance]] that would be worth merging. I left a message at the creator's talk page ([[User talk:Julie.summey]]) saying so, but she never responded, consequently the article never came up on my watchlist again, and I forgot about it. I would favor turning it into a redirect. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 19:22, 12 August 2009 (UTC)
::: I tend to agree... the only way to save that article is to make it clear that this is a sort of pop-psych fallacy. I think that this has already been noted in other places, but it might be worth mentioning explicitly in an article with that title. Or, it could just be too much hassle and a fight to keep it. If we have some people that are willing to take it on, then it might be a service the wikipedia using world to make sure that it's clear that this is a popular misconception, but a misconception nonetheless. Otherwise, just redirect here and include some discussion of the fact that these are popular misconceptions? [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 19:28, 12 August 2009 (UTC)

:::: I agree with Looie. There's no real science here, just pop-psych, and the content already present at Lateralization of Brain Function is better science, better explained, and better referenced. I would support deleting this article and turning it into a redirect to both the neuromyths article (if we can do that) and the lateralization article. [[User:Mirafra|Mirafra]] ([[User talk:Mirafra|talk]]) 20:10, 12 August 2009 (UTC)

:::::I think merging (on paper) is better - I doubt an AfD would reach consensus and the result would likely be a merge anyway. I have not looked at the articles in detail - I just woke up and require coffee to get my hemispheres working more..... [[User:Casliber|Casliber]] ([[User talk:Casliber|talk]] '''·''' [[Special:Contributions/Casliber|contribs]]) 20:50, 12 August 2009 (UTC)

I moved the article to the correct title (lower-case initials) and did some copy-editing on it, bringing it closer to the norms of [[WP:MOS]]. I looked at the history and found that the person who wrote it hasn't done anything else on Wikipedia. I sent her an email saying two concerns had been expressed in regard to the article: that it should get merged into this one, and that few other articles link to it (just one, actually). [[User:Michael Hardy|Michael Hardy]] ([[User talk:Michael Hardy|talk]]) 21:02, 12 August 2009 (UTC)

== The Master and His Emissary ==

''[[The Master and His Emissary]]: The Divided Brain and the Making of the Western World'' is a new study of the specialist hemispheric functioning of the brain, and the conflict between their world views, by the psychiatrist and writer Iain McGilchrist. Published 2009. [[User:Esowteric|Esowteric]]+[[User talk:Esowteric|Talk]] 16:13, 21 December 2009 (UTC)
: As ''The Economist'' notes in their review, McGilchrist seems to take astonishingly liberties with the scientific literature [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 18:00, 22 December 2009 (UTC)
::But the reader is also treated to some very loose talk and to generalisations of breathtaking sweep. The left’s world is “ultimately narcissistic”; its “prime motivation is power”, and the Industrial Revolution was, in some mysterious sense, the left’s “most audacious assault yet on the world of the right hemisphere”. The sainted right, by contrast, has “ideals” that are in harmony with an “essentially local, agrarian, communitarian, organic” conception of democracy... But he offers no evidence that such differences can be explained in physiological terms... The book ends with a deflating admission that will not surprise those readers who feel the author’s main claims about the cerebral hemispheres have the ring of loose analogies rather than hard explanations. Mr McGilchrist would not be unhappy to learn that what he has to say about the roles of the hemispheres in Western culture is simply a metaphor and is not literally true. In other words, he seems to be in two minds about his own thesis, which is fitting but not encouraging.
:::Have expanded and balanced the article a bit now. Apparently the philosopher [[Mary Midgley]] will be reviewing the book in [[The Guardian]] in early January 2010. Will see what she has to say. [[User:Esowteric|Esowteric]]+[[User talk:Esowteric|Talk]] 19:31, 25 December 2009 (UTC)
* The book is published by [[Yale University Press]]. That is a [[Wikipedia:NPOV#Explanation_of_the_neutral_point_of_view|significant]] publisher. Whether we think it is hard science, metaphor or philosophy, a book by them addressing this specific topic is a RS and a bona fide addition. --'''[[User:Jayen466|JN]][[User_Talk:Jayen466|466]]''' 20:41, 25 December 2009 (UTC)
::Actually, it does matter. See [[WP:FRINGE]] and [[WP:UNDUE]]. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 02:49, 27 December 2009 (UTC)
::: To clarify, it does not matter for the entry on the book, itself. We should have an entry on the book. But, given that this book does not purport to actually provide any factually correct information on the topic of ''this article'', lateralization of brain function, but rather uses it as a "loose analog[y]" or a "metaphor" that is "not literally true", it should not be included on ''this page'' due to the wikipedia policies cited above. [[User:Edhubbard|Edhubbard]] ([[User talk:Edhubbard|talk]]) 02:53, 27 December 2009 (UTC)
::::'''Comment''' What we're talking about here is my attempt to include the book in "further reading", an action that was [http://en.wikipedia.org/w/index.php?title=Lateralization_of_brain_function&action=historysubmit&diff=333312394&oldid=333115114 reverted]. I can appreciate your desire to keep what you see as "poppsych" weeded out of the article, so that it is not flagged as "pseudoscience" (whilst remembering that this is not someone's "recommended reading list" but a representative list of "further reading"). However, I think it's a little unfair to base your judgement on the reaction of a reviewer in ''The Economist''. The [http://www.iainmcgilchrist.com/The_Master_and_his_Emissary_by_McGilchrist.pdf introduction to the book (pdf)] seems to paint a different picture of the book's actual content.
::::I like to run articles past their subjects and the author points out to me that "As to the neuropsychological, neurophysiological and other evidence, there are about 3,000 references to the literature included in the notes", and he himself dismisses what he sees as some popular misconceptions about lateralization, though I am reliant on input from reliable sources and cannot of course use phrases like "meticulously documented" until reliable sources use such phraseology. Further reading could perhaps be split into "mainstream" and "<strike>fringe</strike>" "popular psychology" (again remembering that heliocentricity was at one time dismissed as "fringe" theory :)), if it can be established that this is fringe theory, in order not to give undue weight to the less popular mainstream. Just a thought, [[User:Esowteric|Esowteric]]+[[User talk:Esowteric|Talk]] 11:26, 27 December 2009 (UTC)
:None of the reviewers appear to have scientific credentials, as far as I can see. A book of this sort is likely to be reviewed by ''Science'' or ''Nature'' soon, if it hasn't been already, and reviews there would give a much better idea of whether this is a suitable book to direct readers toward for further information. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 14:49, 27 December 2009 (UTC)
::Yes, that seems fair enough. [[User:Esowteric|Esowteric]]+[[User talk:Esowteric|Talk]] 15:01, 27 December 2009 (UTC)

== Connection between Broca's and Wernicke’s ==

Moved existing comment from the article to here: [[Special:Contributions/69.62.226.199|69.62.226.199]] ([[User talk:69.62.226.199|talk]]) 22:30, 23 May 2010 (UTC)
:The first sentence Area and Wernicke’s Area are linked by a white matter fiber tract, the arcuate fasciculus.is explicitly negated in this article http://en.wikipedia.org/wiki/Arcuate_fasciculus.
[edit]

::The article [[Arcuate fasciculus]] explicitly states (cited) that, while it was believed to connect Broca's area and Wernicke's area, it is no longer believed to do so. I don't have the time now to figure out what should be incorporated into this article, but I did want to be sure to bring it to the attention of hopefully anyone involved with this page. -- [[User:Natalya|Natalya]] 21:35, 12 July 2011 (UTC)

:::I think the truth is that the cellular-level synaptic connections and boundaries of Broca's, Wernicke's, and really any other area of the cortex are poorly understood, and therefore an accurate but still helpful statement might be, e.g., "the arcuate fasciculus connects the lateral prefrontal cortex (including Broca's area) with the posterior parietal and temporal cortex (including Wernicke's area) and has been shown to play a role in language processing." (See, e.g., <ref name="Catani et al 2007">{{Cite pmid|17939998}}</ref>.) [[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 15:01, 12 September 2011 (UTC)

Cerebrum

2011-09-12T14:31:17Z

PhineasG:

{{Infobox Brain|
Name = Cerebrum |
Latin = |
GraySubject = |
GrayPage = |
Map --[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC) = Cerebrum map|
MapPos = |
MapCaption = The lobes of the cerebral cortex include the [[frontal lobe|frontal]] (blue), [[temporal lobe|temporal]] (green), [[occipital lobe|occipital]] (red), and [[parietal lobe]]s (yellow). The [[cerebellum]] (unlabeled) is not part of the telencephalon. |
Image2 = EmbryonicBrain.svg |
Caption2 = Diagram depicting the main subdivisions of the embryonic vertebrate brain. |
IsPartOf = |
Components = |
Artery = [[anterior cerebral artery|anterior cerebral]], [[middle cerebral artery|middle cerebral]], [[posterior cerebral artery|posterior cerebral]] |
Vein = [[cerebral veins]] |
BrainInfoType = |
BrainInfoNumber = |
MeshName = Telencephalon |
MeshNumber = A08.186.21.730.885 |
NeuroLex = Cerebrum
| NeuroLexID = birnlex_1042 |
DorlandsPre = |
DorlandsSuf = |
}}
The '''cerebrum''' or '''telencephalon''', together with the [[diencephalon]], constitutes the [[forebrain]]. The cerebrum is the most [[anterior]] (or, in humans, most [[Neuroanatomy#Orientation in neuroanatomy|superior]]) region of the [[vertebrate]] [[central nervous system]]. '''Telencephalon''' refers to the embryonic structure, from which the mature '''cerebrum''' develops. In mammals, the [[Dorsum (biology)|dorsal]] telencephalon, or [[Pallium (neuroanatomy)|pallium]], develops into the [[cerebral cortex]], and the [[ventral]] telencephalon, or [[subpallium]], becomes the [[basal ganglia]]. The cerebrum is also divided into approximately symmetric [[Lateralization of brain function|left and right cerebral hemispheres.]]

With the assistance of the [[cerebellum]], the cerebrum controls all voluntary actions in the body.

== Development ==
During vertebrate embryonic development, the [[prosencephalon]], the most anterior of three [[vesicle (biology)|vesicle]]s that form from the [[embryo]]nic [[neural tube]], is further subdivided into the telencephalon and [[diencephalon]]. The telencephalon then forms two lateral telencephalic vesicles which develop into the left and right cerebral hemispheres.

== Structure ==
The cerebrum is composed of the following sub-regions:
* [[Cerebral cortex]], or cortices of the cerebral hemispheres
* [[Basal ganglia]], or basal nuclei
* [[Limbic System]]

== Composition ==
[[File:Cerebrum animation small.gif|thumb|Location of the human cerebrum (red).]]
The cerebrum comprises what most people think of as the "[[brain]]." It lies in front or on top of the [[brainstem]] and in humans is the largest and most well-developed of the five major divisions of the brain. The cerebrum is the newest structure in the [[phylogenetic]] sense, with [[mammal]]s having the largest and most well-developed among all [[species]]. In larger mammals, the cerebral cortex is folded into many gyri and sulci, which has allowed the cortex to expand in surface area without taking up much greater volume.

In [[human]]s, the cerebrum surrounds older parts of the brain. [[Limbic]], [[olfactory]], and [[motor systems]] project fibers from the cerebrum to the [[brainstem]] and [[spinal cord]]. [[Cognition|Cognitive]] and [[volition (psychology)|volitive]] systems project fibers from the cerebrum to the [[thalamus]] and to specific regions of the [[midbrain]]. The neural networks of the cerebrum facilitate complex behaviors such as social interactions, thought, judgement, learning, [[working memory]], and in humans, speech and [[language]].

== Functions ==
'''Note''': As the cerebrum is a gross division with many subdivisions and sub-regions, it is important to state that this section lists the functions that the cerebrum ''as a whole'' serves. See main articles on [[cerebral cortex]] and [[basal ganglia]] for more information.

=== Movement ===
The cerebrum directs the conscious or volitional motor functions of the body. These functions originate within the [[primary motor cortex]] and other frontal lobe motor areas where actions are planned. [[Upper motor neuron]]s in the primary motor cortex send their [[axon]]s to the brainstem and spinal cord to [[synapse]] on the [[lower motor neurons]], which innervate the muscles. Damage to motor areas of cortex can lead to certain types of [[motor neuron disease]]. This kind of damage results in loss of muscular power and precision rather than total [[paralysis]].

=== Sensory processing ===
The primary sensory areas of the [[cerebral cortex]] receive and process visual, auditory, [[somatosensory]], [[gustatory]], and [[olfactory]] information. Together with association cortical areas, these brain regions synthesize sensory information into our perceptions of the world around us.

=== Olfaction ===
{{Main|Olfaction}}
The [[olfactory bulb]] in most vertebrates is the most anterior portion of the cerebrum, and makes up a relatively large proportion of the telencephalon. However, in humans, this part of the brain is much smaller, and lies underneath the frontal lobe. The olfactory sensory system is unique in the sense that neurons in the olfactory bulb send their axons directly to the [[piriform cortex|olfactory cortex]], rather than to the [[thalamus]] first. Damage to the olfactory bulb results in a loss of the sense of smell.

=== Language and communication ===
{{Main|Language}}
[[Speech communication|Speech]] and language are mainly attributed to parts of the cerebral cortex. Motor portions of language are attributed to [[Broca's area]] within the frontal lobe. Speech comprehension is attributed to [[Wernicke's area]], at the temporal-parietal lobe junction. These two regions are interconnected by a large [[white matter]] tract, the [[arcuate fasciculus]]. Damage to the Broca's area results in [[expressive aphasia]] (non-fluent aphasia) while damage to Wernicke's area results in [[receptive aphasia]] (also called fluent aphasia).

=== Learning and memory ===
{{Main|Memory}}
Explicit or declarative (factual) memory formation is attributed to the [[hippocampus]] and associated regions of the medial temporal lobe. This association was originally described after a patient known as [[HM (patient)|HM]] had both his hippocampuses (left and right) surgically removed to treat severe epilepsy. After surgery, HM had [[anterograde amnesia]], or the inability to form new memories.

Implicit or procedural memory, such as complex motor behaviors, involves the basal ganglia.

== Cell regeneration in ''Xenopus laevis'' ==
=== Larval stage ===
In a study of the telencephalon conducted in [[Hokkaido University]] on [[African clawed frog]]s (''Xenopus laevis''){{ref|Yoshino}}, it was discovered that, during [[larva]]l stages, the telencephalon was able to regenerate around half of the anterior portion (otherwise known as '''partially truncated'''), after a reconstruction of a would-be accident, or malformation of features.

The regeneration and active proliferation of cells within the clawed frog is quite remarkable, regenerated cells being almost functionally identical to the ones originally found in the brain after birth, despite the lack of brain matter for a sustained period of time.

This kind of regeneration depends on ependymal layer cells covering the cerebral lateral ventricles, within a short period before, or within the initial stage of wound-healing. This is observed within the stages of healing within larvae of the clawed frog.

=== Developed stage ===
The regeneration within the developed stage of the clawed frog is different from that in the larval stage. Because the cells adhere to one another, they are unable to form an entity that can cover the cerebral lateral ventricles. Thus, the telencephalon remains truncated and the loss of function becomes permanent.

=== Effects of abnormality ===
After removing over half of the telencephalon in the developed stage of the clawed frog, the lack of functions within the animal was apparent, manifesting with obvious difficulties in movement, [[nonverbal communication]] between other species, as well as other difficulties thought to be similar to those seen in humans.

This kind of regeneration is still relatively unknown in regard to regeneration within larval stages, similar to the human [[fetus|fetal stage]].

==Variation among species==
In the most primitive living vertebrates, the [[hagfish]]es and [[lamprey]]s, the cerebrum is a relatively simple structure receiving nerve impulses from the [[olfactory bulb]]. In [[cartilaginous]] and [[lobe-finned fish]]es, and also in [[amphibian]]s, a more complex structure is present, with the cerebrum being divided into three distinct regions. The lowermost (or ventral) region forms the basal nuclei, and contains fibres connecting the rest of the cerebrum to the [[thalamus]]. Above this, and forming the lateral part of the cerebrum, is the ''paleopallium'', while the uppermost (or dorsal) part is referred to as the ''archipallium''. The cerebrum remains largely devoted to olfactory sensation in these animals, despite its much wider range of functions in [[amniote]]s.{{ref|VB}}

In [[ray-finned fish]]es, the structure is somewhat different. The inner surfaces of the lateral and ventral regions of the cerebrum bulge up into the ventricles; these include both the basal nuclei and the various parts of the pallium, and may be complex in structure, especially in [[teleost]]s. The dorsal surface of the cerebrum is membranous, and does not contain any nervous tissue.{{ref|VB}}

In the amniotes, the cerebrum becomes increasingly large and complex. In [[reptile]]s, the paleopallium is much larger than in amphibians, and its growth has pushed the basal nuclei into the central regions of the cerebrum. As in the lower vertebrates, the grey matter is generally located beneath the white matter, but in some reptiles, it spreads out to the surface to form a primitive cortex, especially in the anterior part of the brain.{{ref|VB}}

In [[mammal]]s, this development proceeds further, so that the cortex covers almost the whole of the cerebral hemispheres, especially in more "advanced" species, such as [[primate]]s. The paleopallium is pushed to the ventral surface of the brain, where it becomes the olfactory lobes, while the archipallium becomes rolled over at the medial dorsal edge to form the [[hippocampus]]. In [[placental mammal]]s, a [[corpus callosum]] also develops, further connecting the two hemispheres. The complex convolutions of the cerebral surface are also found only in higher mammals.{{ref|VB}}

The cerebrum of [[bird]]s has evolved along different lines to that of mammals, although they are similarly enlarged, by comparison with reptiles. However, this enlargement is largely due to the basal ganglia, with the other areas remaining relatively primitive in structure. For example, there is no great expansion of the cerebral cortex, as there is in mammals. Instead, an [[High vocal center|HVC]] develops just above the basal ganglia, and this appears to be the area of the bird brain most concerned with learning complex tasks.{{ref|VB}}

== See also==
* [[List of regions in the human brain]]
* [[Cerebral cortex]]
* [[Basal ganglia]]

== References ==
#{{note|Levi-Oppenheim}} Levi-Montalcini, R. (1949). Proliferation, differentiation and degeneration in the spinal ganglia of the chick embryo under normal and experimental conditions. Pages 450–502.
#{{note|Yoshino}} Yoshino J, Tochinai S. Successful reconstitution of the non-regenerating adult telencephalon by cell transplantation in Xenopus laevis. ''Dev Growth Differ.'' 2004;46(6):523–34. PMID 15610142.
#{{note|Yaginuma}} Yaginuma, H., Tomita, M., Takashita, N., McKay, S., Cardwell, C., Yin, Q. Aminobuytric acid immunoreactivity within the human cerebral cortex. Pages 481–500.
#{{note|Haydar}} Haydar, T. F, Kuan, C., Y., Flavell, R. A. & Rakic, P. (1999) The role of cell death in regulating the size and shape of the mammalian forebrain. Pages 621–626.
#{{note|VB}} {{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 536–543|isbn= 0-03-910284-X}}

==External links==
* [http://www.rahulgladwin.com/blog/2006/06/cerebrum-higher-integrative-functions.html Cerebrum Medical Notes on rahulgladwin.com]
* [http://www.neuinfo.org/nif/nifgwt.html?query=%22Cerebrum%22 NIF Search - Cerebrum] via the [[Neuroscience Information Framework]]

{{Nervous system}}
{{Cerebral cortex}}
{{Commissural fibers}}
{{Lateral ventricles}}
{{Rostral basal ganglia and associated structures}}
{{Association fibers}}

[[Category:Cerebrum| ]]

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[[ca:Telencèfal]]
[[cs:Koncový mozek]]
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[[eo:Grandcerbo]]
[[fa:مخ]]
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[[it:Telencefalo]]
[[he:המוח הגדול]]
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[[no:Telencephalon]]
[[pl:Kresomózgowie]]
[[ro:Telencefal]]
[[ru:Конечный мозг]]
[[simple:Cerebrum]]
[[sk:Koncový mozog]]
[[fi:Isoaivot]]
[[sv:Storhjärna]]
[[th:ซีรีบรัม]]
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Talk:Cerebrum

2011-09-12T14:28:06Z

PhineasG:

{{WikiProject Neuroscience|class=C|importance=High}}
{{WikiProject Medicine|class=C|importance=Low|neurology=yes|neurology-imp=Mid}}

[[User:Bird|Bird]]

There's an accuracy dispute tag that's been here since early March, but absolutely no indication of what the dispute is over or that there's any work being done to resolve it. I'm removing it. [[User:Bryan Derksen|Bryan]] 04:18, 26 Sep 2004 (UTC)

"'''...cerebrum to thalamic nuclei and to other regions of the brainstem."''' This is gramatically incorrect unless the author means to include the Thalamus in the Brainstem. Some would, but the separateness of the Thalamic nuclei and their cortical complements is an illusion of anatomy. Inclusion of the Thalamus in reference to that thing called the brain 'Stem' is an antiquity, at best, ought to be abandoned, and usually is. tombronson@yahoo.com 7:32 6/17/05

== Thanks for the cleanup ==

Hey! Thanks for cleaning up my article, i was going to add references, but i just wanted to make sure that all the relevant information was added. So, thanks for beating me to it!

I'll be trying to get some book references shortly, and there will be more information added for expansion, but until then, thanks to ye who beat me to it! *giggles*
([[User:JessicaX|JessicaX]] 08:13, 27 September 2005 (UTC))

== Absolutely jumpstarted the article ==
Hey guys, i've got 18 books, free time, and my science cap is on. I'm going to do MAJOR edits on this article, the majority of information i'm adding does not come close :D.

Thanks!
([[User:JessicaX|Jessica(Succeeded)]] 20:55, 7 October 2005 (UTC))

== Does this really need to be a stub? ==

It looks reasonably comprehensive to me. [[User:Weebs|Weebs]] 09:30, 16 October 2005 (UTC)
:*Indeed, it does not need to be. It's been fixed. [[User:Semiconscious|semiconscious]] ([[User talk:Semiconscious|talk]] · [http://socrates.berkeley.edu/~btvoytek home]) 21:38, 16 October 2005 (UTC)

== Deleted text ==

I deleted this from the end of the first sentence of the intro, "..., which some groups would class as unique features that make [[Homosapien|humans]] different from other species." Reason: weasel words, "some groups." Which groups? Groups of scientists, clergymen, Hollywood actors? --[[User:TheLimbicOne|TheLimbicOne]]([[user talk:TheLimbicOne|talk]]) 13:34, 7 April 2006 (UTC)

-----

== More Info. ==

I was looking for information on what type of tissues/cells its made of. Maybe I missed it, but I don't beleive it was in there. [[User:70.39.64.254|70.39.64.254]] 19:56, 28 January 2007 (UTC)[[Superllama08]]

== image consistency==
There are at least three different images that are used to show the relationships various lobes of the cerebrum. There's [[Image:Brainlobes.svg|100px|Image:Brainlobes.svg]] which is used on the Temporal and Occipital lobe pages, [[Image:Gray728.png|100px|Image:Gray728.png]], which is used on the Parietal and Frontal lobe pages, and [[Image:Brain-anatomy.jpg|100px|Image:Brain-anatomy.jpg]] on this page.

Wouldn't it a better if one of these images was selected and used across all five pages? It would make for more visual consistency across them. [[User:Yvain|Yvain]] 13:00, 14 May 2006 (UTC)

:I would support that. Of the three, I like the middle one the best. --[[User:Arcadian|Arcadian]] 14:37, 14 May 2006 (UTC)
:The Gray's image is nice. I've updated the lobe pages to use it. --[[User:Diberri|David Iberri]] ([[User talk:Diberri|talk]]) 15:31, 14 May 2006 (UTC)

== Apoptosis details - do they belong here? ==
Isn't that information on the morphological effects of apoptosis general to most tissues and cell types? You know - the membrane blebbage, pyknosis, etc. Does it really belong on a telencephalon page? [[User:130.91.11.117|130.91.11.117]] 13:30, 9 August 2006
: This struck me as odd too, wanted to ask the same question. --[[User:CopperKettle|CopperKettle]] 07:38, 12 September 2006 (UTC)
: I agree. As your comments are over a year old with no other responses, I will remove the cell death section unless anyone objects.[[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 17:13, 12 February 2008 (UTC)

== Dorsal and ventral telencephalon ==
[http://biology.plosjournals.org/perlserv?request=get-document&doi=10.1371/journal.pbio.0030186 Stumbled] upon this sentence: "The telencephalon is subdivided into '''dorsal (pallial)''' and '''ventral (subpallial)''' territories, which give rise to the cerebral cortex and the underlying basal ganglia, respectively. " Should this information be included in the article? --[[User:CopperKettle|CopperKettle]] 07:35, 12 September 2006 (UTC)
:Moreover, in the "[[avian pallium]]" article, there is also a mention of dorsal and ventral telencephalon subdivisions:
:''In the anatomy of animals, an avian pallium is the '''dorsal telencephalon''' of a bird's brain. The subpallium is the '''ventral telencephalon'''.''
:--[[User:CopperKettle|CopperKettle]] 11:23, 12 September 2006 (UTC)

== Division of Brain ==

Firstly, I think that the title should be changed to cerebrum, because it is more common and more useful to those that are researching this topic. Most college textbooks call this part the cerebrum as it should be title.

Many Psychologists do not consider the Limbic System as part of the Cerebrum. (According to my textbook, anyway. Myers 8th Edition)

I did not take the liberty to change any of this since I'd rather have a discussion and have it changed with the agreement from others.

NK.

EDIT:
My AP test once asked me to desribe the difference in the way different parts of the brain aid adaptation. Two of them were the cerebrum and limbic system. A little paradoxical if you consider this wikiarticle, don't you think?
[[User:68.4.82.151|68.4.82.151]] 07:20, 5 January 2007 (UTC)

:Cerebrum is an ambivalent term, as opposed to telencephalon. The latter term should therefore be preferred. Classifying the limbic system as part of the cerebrum or not is an anatomist's job, not a psychologist's. ;-) According to the Unified Medical Language System ([[UMLS]]), the limbic system is defined thusly:

::"For most authors, it includes the AMYGDALA; EPITHALAMUS; GYRUS CINGULI; hippocampal formation (see HIPPOCAMPUS); HYPOTHALAMUS; PARAHIPPOCAMPAL GYRUS; SEPTAL NUCLEI; anterior nuclear group of thalamus, and portions of the basal ganglia. (Parent, Carpenter's Human Neuroanatomy, 9th ed, p744; NeuroNames, http://rprcsgi.rprc.washington.edu/neuronames/index.html (September 2, 1998))"

:Of those, at least the epithalamus and the hypothalamus are part of the diencephalon. It is therefore sloppy to say that the telencephalon consists of, among other things, the limbic system. Rather, the limbic system is located partly in the telencephalon. Furthermore, saying that any structure consists of one or more systems is ontologically incorrect, since it confuses objects and functions. -- Ernest

::It's an anatomist's job to say what they think they see, but they aren't gods. If psychologists have some reason to consider the function of the limbic system as being so different from the function of the lobular structure above it, then perhaps it really is a good reason to narrow the terminology. Within their field, they no doubt have narrowed the terminology of "Cerebrum" to exclude the limbic system; perhaps this will become the established definition.
::In any case, I find it ridiculous that this article is not title '''cerebrum''' since that is, in fact, what all secondary students will be told the name is. [[User:ManVhv|ManVhv]] 17:25, 9 June 2007 (UTC)

== Renaming to Cerebrum ==

I agree with Earnest. As a senior biology student, I have never come across the term 'Telencephalon' as a substitute for cerebrum, and I doubt any of my fellow students have either. I suppose it doesn't matter as along as cerebrum redirects, but it is confusing when reading the article.
[[User:Haylo17|Haylo17]] 04:53, 27 May 2007 (UTC)Haylo

:Adding to the discussion. While I don't have a source to cite right now (I probably can find one on Tuesday but until then this is OR, sorry), Cerebrum is a term based on adult anatomy, whereas telencephalon refers to structures based on their developmental lineage. That said, the terms refer to the same structure. As for which term is used more frequent, I guess it depends on your field of study. If you are a functional neuroanatomist or neurophysiologist (as I am) it would be hard to imagine ever using the term telencephalon rather than cerebrum. Whereas, I imagine developmental biologists or developmental neuroscientists would feel just as strongly that cerebrum is a crude term for the structure. A quick NLM/PubMed search reveals roughly equal usage of both terms (226323 vs 228060 papers) with considerable overlap (224892). That is to say, of the nearly quarter million peer reviewed scientific journal articles dealing with the topic, only 1431 use ''just'' the term ''telencephalon'', 3168 use just the term ''cerebrum'', and 224892 use both. I would vote to use the term telencephalon when talking about development and the term cerebrum when talking about function. --'''[[User:Selket|Selket]]''' [[User_talk:Selket|Talk]] 05:26, 27 May 2007 (UTC

==Requested move==
[[Cerebrum(brain struture)]] → [[Cerebrum]] — I have requested that this page be moved to [[Cerebrum]]. There is no need for the disambiguating (brain structure) in the title of the page. I can't do the move myself because [[Cerebrum]] is currently a redirect page, and there also appears to be some controversy about whether the article should be called cerebrum or telencephalon. In addition, when this page was moved from telencephalon it resulted in a [[WP:2R|double redirect]], and two typos (missing space and missing "c"). At the very least it should be [[Cerebrum (brain structure)]], not [[Cerebrum(brain struture)]]. —[[User:Dcooper|Dcooper]] 17:06, 10 July 2007 (UTC)

''This article has been renamed {{{{{subst|}}}#if:{{{1|}}}|from [[{{{1}}}]] to [[{{{2}}}]]}} as the result of a [[wikipedia:requested moves|move request]].'' --[[User:Stemonitis|Stemonitis]] 17:24, 10 July 2007 (UTC)

==Olfaction Section is Incorrect==
Someone edited the Olfaction section so that rather than referring to the sense of smell it has some nonsense about controlling movement when the rest of the brain is dead, and restoring lost memories. —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/68.209.169.246|68.209.169.246]] ([[User talk:68.209.169.246|talk]]) 20:54, 8 December 2007 (UTC) 

== Cerebrum anterior? ==

The first line of the article says '''"The telencephalon (pronounced /tɛlɛnˈsɛfəlɒn/), cerebrum, or forebrain is the most anterior region of the brain."'''. I think this is a bit misleading. The cerebrum is only really the most anterior region in the embryonic brain. When fully developed it is really the most dorsal region of the brain as it sits roughly on top of the mid brain and cerebellum. In any case I think either terminology is slightly clumsy and perhaps confusing for the layman - which is bad in the introduction. Better would be to just say it is the uppermost region of the brain or perhaps skip the location all together and just give a picture. What do you think? [[User:Ralphmcd|Ralphmcd]] ([[User talk:Ralphmcd|talk]]) 11:24, 22 February 2008 (UTC)

:The cerebrum is only "on top" of the rest of the brain in humans (and maybe some primates?). In the vast majority of mammals it is actually anterior. I see your point, though; unfortunately many of the brain-related articles here are unclear at best about whether they're referring to human brain or to mammalian brain in general, or.... It's a big job to start going through and clarifying everywhere, but we should always be specific whenever possible.[[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 22:17, 25 February 2008 (UTC)

:Opps, never ocurred to me that the article referred to brains in general - I feel a bit stupid. Still, I think since the article and the picture refers mostly to the human brain some clarification is in order. Perhaps keep the first paragraph and then go on to explain it's location in the human brain in the second. I don't have time to think about it today but if no one has any objections I may change this tomorrow. [[User:Ralphmcd|Ralphmcd]] ([[User talk:Ralphmcd|talk]]) 23:44, 25 February 2008 (UTC)

::OK, you changed it while I was writing that post. Nice one. Ignore my last post. [[User:Ralphmcd|Ralphmcd]] ([[User talk:Ralphmcd|talk]]) 23:47, 25 February 2008 (UTC)

== Cerebrum/Telencephalon - Developmental connotations? ==

The page seems to indicate that telencephalon is the immature/embryological precursor to the mature cerebrum. I think this is misleading - I'm not an expert (just a Med student) but I believe the two words have different etymological origins (as discussed by others above) and that telencephalon is preferred under naming conventions as it is more consistent with other regions (diencephalon etc.) Either way, I don't believe either of them have temporal or developmental connotations, but I could be wrong.
[[User:k0911|k0911]] 15:19, 09 May 2009 (UTC) —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/137.73.88.101|137.73.88.101]] ([[User talk:137.73.88.101|talk]])  

== Re new info on comparative studies ==

Nice to see all the information added. I'd like to mention that my understanding is that Romer's conceptions are out of date in a few respects. First, I believe that the current consensus is that the teleost cerebrum is "everted", i.e., turned inside out like a sock, so that the structures that line the ventricles in most vertebrates are on the outside in teleosts. Second, I don't think the terms "archipallium" and "paleopallium" are commonly used any more -- the terms "medial pallium", "dorsal pallium", "lateral pallium", and sometimes "ventral pallium" are used instead. Also I don't think it is any longer accepted that the cerebrum is entirely dominated by olfaction in lamprey and hagfish, but I could be wrong about this. Finally there ought to be some mention of the basal ganglia, which are clearly present in all vertebrates including lamprey. I think the added material improves the article; these are basically comments aimed at possible further improvements in the future. [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 17:12, 11 November 2009 (UTC)

== very inaccurate ==

Not sure I will have time to help much with this, but among other things:
"cerebral cortex" is a mammalian structure. It exists only in mammals. The dorsal pallium or "forebrain" in the other vertebrate species have different structures and different names, and should not be called cerebral cortex.
Birds have highly developed forebrains. HVC is but one nucleus in the forebrain, not the whole thing. The bird forebrain, like the cerebral cortex, can achieve high levels of what we call intelligence -- by some measures, crows and ravens and some parrots are as smart as any primate except humans.
I'm virtually certain (but epsilon less than 100%) that the olfactory bulb is not part of the telencephelon.

Georg Striedter is an expert and leading researcher in brain evolution, some of his review articles or his book should be illuminating for this article. See also the book Comparative Vertebrate Neuroanatomy: Evolution and Adaptation by Ann B. Butler and William Hodos. —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Kdmkdm|Kdmkdm]] ([[User talk:Kdmkdm|talk]] • [[Special:Contributions/Kdmkdm|contribs]]) 17:27, 23 October 2010 (UTC) 

== Remove X. laevis section? ==
The section "Cell regeneration in Xenopus laevis" seems not to belong here, but rather perhaps in an article elsewhere on nervous system regeneration/plasticity/development. Also, it appears to be a summary of a single scientific paper. I suggest removing it and will do so soon unless anyone objects.[[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 14:28, 12 September 2011 (UTC)

Cerebrum

2011-09-12T14:14:49Z

PhineasG: refined intro paragraph. removed empty "hemispheres" section.

{{Infobox Brain|
Name = Cerebrum |
Latin = |
GraySubject = |
GrayPage = |
Map --[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC) = Cerebrum map|
MapPos = |
MapCaption = The lobes of the cerebral cortex include the [[frontal lobe|frontal]] (blue), [[temporal lobe|temporal]] (green), [[occipital lobe|occipital]] (red), and [[parietal lobe]]s (yellow). The [[cerebellum]] (unlabeled) is not part of the telencephalon. |
Image2 = EmbryonicBrain.svg |
Caption2 = Diagram depicting the main subdivisions of the embryonic vertebrate brain. |
IsPartOf = |
Components = |
Artery = [[anterior cerebral artery|anterior cerebral]], [[middle cerebral artery|middle cerebral]], [[posterior cerebral artery|posterior cerebral]] |
Vein = [[cerebral veins]] |
BrainInfoType = |
BrainInfoNumber = |
MeshName = Telencephalon |
MeshNumber = A08.186.21.730.885 |
NeuroLex = Cerebrum
| NeuroLexID = birnlex_1042 |
DorlandsPre = |
DorlandsSuf = |
}}
The '''cerebrum''' or '''telencephalon''', together with the [[diencephalon]], constitutes the [[forebrain]]. The cerebrum is the most [[anterior]] (or, in humans, most [[Neuroanatomy#Orientation in neuroanatomy|superior]]) region of the [[vertebrate]] [[central nervous system]]. '''Telencephalon''' refers to the embryonic structure, from which the mature '''cerebrum''' develops. The [[Dorsum (biology)|dorsal]] telencephalon, or [[Pallium (neuroanatomy)|pallium]], develops into the [[cerebral cortex]], and the [[ventral]] telencephalon, or [[subpallium]], becomes the [[basal ganglia]]. The cerebrum is also divided into symmetric left and right cerebral hemispheres.

With the assistance of the [[cerebellum]], the cerebrum controls all voluntary actions in the body.

== Development ==
During vertebrate embryonic development, the [[prosencephalon]], the most anterior of three [[vesicle (biology)|vesicle]]s that form from the [[embryo]]nic [[neural tube]], is further subdivided into the telencephalon and [[diencephalon]]. The telencephalon then forms two lateral telencephalic vesicles which develop into the left and right cerebral hemispheres.

== Structure ==
The cerebrum is composed of the following sub-regions:
* [[Cerebral cortex]], or cortices of the cerebral hemispheres
* [[Basal ganglia]], or basal nuclei
* [[Limbic System]]

== Composition ==
[[File:Cerebrum animation small.gif|thumb|Location of the human cerebrum (red).]]
The cerebrum comprises what most people think of as the "[[brain]]." It lies in front or on top of the [[brainstem]] and in humans is the largest and most well-developed of the five major divisions of the brain. The cerebrum is the newest structure in the [[phylogenetic]] sense, with [[mammal]]s having the largest and most well-developed among all [[species]]. In larger mammals, the cerebral cortex is folded into many gyri and sulci, which has allowed the cortex to expand in surface area without taking up much greater volume.

In [[human]]s, the cerebrum surrounds older parts of the brain. [[Limbic]], [[olfactory]], and [[motor systems]] project fibers from the cerebrum to the [[brainstem]] and [[spinal cord]]. [[Cognition|Cognitive]] and [[volition (psychology)|volitive]] systems project fibers from the cerebrum to the [[thalamus]] and to specific regions of the [[midbrain]]. The neural networks of the cerebrum facilitate complex behaviors such as social interactions, thought, judgement, learning, [[working memory]], and in humans, speech and [[language]].

== Functions ==
'''Note''': As the cerebrum is a gross division with many subdivisions and sub-regions, it is important to state that this section lists the functions that the cerebrum ''as a whole'' serves. See main articles on [[cerebral cortex]] and [[basal ganglia]] for more information.

=== Movement ===
The cerebrum directs the conscious or volitional motor functions of the body. These functions originate within the [[primary motor cortex]] and other frontal lobe motor areas where actions are planned. [[Upper motor neuron]]s in the primary motor cortex send their [[axon]]s to the brainstem and spinal cord to [[synapse]] on the [[lower motor neurons]], which innervate the muscles. Damage to motor areas of cortex can lead to certain types of [[motor neuron disease]]. This kind of damage results in loss of muscular power and precision rather than total [[paralysis]].

=== Sensory processing ===
The primary sensory areas of the [[cerebral cortex]] receive and process visual, auditory, [[somatosensory]], [[gustatory]], and [[olfactory]] information. Together with association cortical areas, these brain regions synthesize sensory information into our perceptions of the world around us.

=== Olfaction ===
{{Main|Olfaction}}
The [[olfactory bulb]] in most vertebrates is the most anterior portion of the cerebrum, and makes up a relatively large proportion of the telencephalon. However, in humans, this part of the brain is much smaller, and lies underneath the frontal lobe. The olfactory sensory system is unique in the sense that neurons in the olfactory bulb send their axons directly to the [[piriform cortex|olfactory cortex]], rather than to the [[thalamus]] first. Damage to the olfactory bulb results in a loss of the sense of smell.

=== Language and communication ===
{{Main|Language}}
[[Speech communication|Speech]] and language are mainly attributed to parts of the cerebral cortex. Motor portions of language are attributed to [[Broca's area]] within the frontal lobe. Speech comprehension is attributed to [[Wernicke's area]], at the temporal-parietal lobe junction. These two regions are interconnected by a large [[white matter]] tract, the [[arcuate fasciculus]]. Damage to the Broca's area results in [[expressive aphasia]] (non-fluent aphasia) while damage to Wernicke's area results in [[receptive aphasia]] (also called fluent aphasia).

=== Learning and memory ===
{{Main|Memory}}
Explicit or declarative (factual) memory formation is attributed to the [[hippocampus]] and associated regions of the medial temporal lobe. This association was originally described after a patient known as [[HM (patient)|HM]] had both his hippocampuses (left and right) surgically removed to treat severe epilepsy. After surgery, HM had [[anterograde amnesia]], or the inability to form new memories.

Implicit or procedural memory, such as complex motor behaviors, involves the basal ganglia.

== Cell regeneration in ''Xenopus laevis'' ==
=== Larval stage ===
In a study of the telencephalon conducted in [[Hokkaido University]] on [[African clawed frog]]s (''Xenopus laevis''){{ref|Yoshino}}, it was discovered that, during [[larva]]l stages, the telencephalon was able to regenerate around half of the anterior portion (otherwise known as '''partially truncated'''), after a reconstruction of a would-be accident, or malformation of features.

The regeneration and active proliferation of cells within the clawed frog is quite remarkable, regenerated cells being almost functionally identical to the ones originally found in the brain after birth, despite the lack of brain matter for a sustained period of time.

This kind of regeneration depends on ependymal layer cells covering the cerebral lateral ventricles, within a short period before, or within the initial stage of wound-healing. This is observed within the stages of healing within larvae of the clawed frog.

=== Developed stage ===
The regeneration within the developed stage of the clawed frog is different from that in the larval stage. Because the cells adhere to one another, they are unable to form an entity that can cover the cerebral lateral ventricles. Thus, the telencephalon remains truncated and the loss of function becomes permanent.

=== Effects of abnormality ===
After removing over half of the telencephalon in the developed stage of the clawed frog, the lack of functions within the animal was apparent, manifesting with obvious difficulties in movement, [[nonverbal communication]] between other species, as well as other difficulties thought to be similar to those seen in humans.

This kind of regeneration is still relatively unknown in regard to regeneration within larval stages, similar to the human [[fetus|fetal stage]].

==Variation among species==
In the most primitive living vertebrates, the [[hagfish]]es and [[lamprey]]s, the cerebrum is a relatively simple structure receiving nerve impulses from the [[olfactory bulb]]. In [[cartilaginous]] and [[lobe-finned fish]]es, and also in [[amphibian]]s, a more complex structure is present, with the cerebrum being divided into three distinct regions. The lowermost (or ventral) region forms the basal nuclei, and contains fibres connecting the rest of the cerebrum to the [[thalamus]]. Above this, and forming the lateral part of the cerebrum, is the ''paleopallium'', while the uppermost (or dorsal) part is referred to as the ''archipallium''. The cerebrum remains largely devoted to olfactory sensation in these animals, despite its much wider range of functions in [[amniote]]s.{{ref|VB}}

In [[ray-finned fish]]es, the structure is somewhat different. The inner surfaces of the lateral and ventral regions of the cerebrum bulge up into the ventricles; these include both the basal nuclei and the various parts of the pallium, and may be complex in structure, especially in [[teleost]]s. The dorsal surface of the cerebrum is membranous, and does not contain any nervous tissue.{{ref|VB}}

In the amniotes, the cerebrum becomes increasingly large and complex. In [[reptile]]s, the paleopallium is much larger than in amphibians, and its growth has pushed the basal nuclei into the central regions of the cerebrum. As in the lower vertebrates, the grey matter is generally located beneath the white matter, but in some reptiles, it spreads out to the surface to form a primitive cortex, especially in the anterior part of the brain.{{ref|VB}}

In [[mammal]]s, this development proceeds further, so that the cortex covers almost the whole of the cerebral hemispheres, especially in more "advanced" species, such as [[primate]]s. The paleopallium is pushed to the ventral surface of the brain, where it becomes the olfactory lobes, while the archipallium becomes rolled over at the medial dorsal edge to form the [[hippocampus]]. In [[placental mammal]]s, a [[corpus callosum]] also develops, further connecting the two hemispheres. The complex convolutions of the cerebral surface are also found only in higher mammals.{{ref|VB}}

The cerebrum of [[bird]]s has evolved along different lines to that of mammals, although they are similarly enlarged, by comparison with reptiles. However, this enlargement is largely due to the basal ganglia, with the other areas remaining relatively primitive in structure. For example, there is no great expansion of the cerebral cortex, as there is in mammals. Instead, an [[High vocal center|HVC]] develops just above the basal ganglia, and this appears to be the area of the bird brain most concerned with learning complex tasks.{{ref|VB}}

== See also==
* [[List of regions in the human brain]]
* [[Cerebral cortex]]
* [[Basal ganglia]]

== References ==
#{{note|Levi-Oppenheim}} Levi-Montalcini, R. (1949). Proliferation, differentiation and degeneration in the spinal ganglia of the chick embryo under normal and experimental conditions. Pages 450–502.
#{{note|Yoshino}} Yoshino J, Tochinai S. Successful reconstitution of the non-regenerating adult telencephalon by cell transplantation in Xenopus laevis. ''Dev Growth Differ.'' 2004;46(6):523–34. PMID 15610142.
#{{note|Yaginuma}} Yaginuma, H., Tomita, M., Takashita, N., McKay, S., Cardwell, C., Yin, Q. Aminobuytric acid immunoreactivity within the human cerebral cortex. Pages 481–500.
#{{note|Haydar}} Haydar, T. F, Kuan, C., Y., Flavell, R. A. & Rakic, P. (1999) The role of cell death in regulating the size and shape of the mammalian forebrain. Pages 621–626.
#{{note|VB}} {{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 536–543|isbn= 0-03-910284-X}}

==External links==
* [http://www.rahulgladwin.com/blog/2006/06/cerebrum-higher-integrative-functions.html Cerebrum Medical Notes on rahulgladwin.com]
* [http://www.neuinfo.org/nif/nifgwt.html?query=%22Cerebrum%22 NIF Search - Cerebrum] via the [[Neuroscience Information Framework]]

{{Nervous system}}
{{Cerebral cortex}}
{{Commissural fibers}}
{{Lateral ventricles}}
{{Rostral basal ganglia and associated structures}}
{{Association fibers}}

[[Category:Cerebrum| ]]

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Neuroanatomy

2011-09-12T14:07:48Z

PhineasG: /* Orientation in neuroanatomy */

{{incomplete|date=January 2010}}
[[Image:Gehirn, medial - beschriftet lat.svg|right|thumbnail|Anatomy of the human brain.]]

'''Neuroanatomy''' is the study of the physical structure and organization of the [[nervous system]]. In contrast to animals with [[radial symmetry]], whose nervous system consists of a distributed network of cells, animals with [[bilateral symmetry]] have segregated, defined nervous systems, and thus we can begin to speak of their neuroanatomy. In [[vertebrates]], both the internal structure of the [[brain]] and [[spinal cord]] (together called the [[central nervous system]], or CNS) and the routes of the nerves that connect to the rest of the body (known as the [[peripheral nervous system]], or PNS) are extremely elaborate. The delineation of distinct structures and regions of the nervous system has been critical in investigating how it works. For example, much of what neuroscientists have learned comes from observing how damage or "lesions" to specific brain areas affects [[behavior]] or other neural functions.

== History ==
The first known written record of a study of the anatomy of the human brain is the ancient Egyptian document the Edwin Smith Papyrus.<ref name = ESSP>Atta, H. M. "Edwin Smith Surgical Papyrus: The Oldest Known Surgical Treatise". American Surgeon, 1999, 65(12), 1190-1192.</ref> The next major development in neuroanatomy was some thousand years later when the Greek Alcmaeon determined that the brain and not the heart ruled the body and that the senses were dependent on the brain.<ref name = RF>Rose, F., "Cerebral Localization in Antiquity". Journal of the History of the Neurosciences, 2009, 18(3), 239-247.</ref>

After Alcmaeon’s findings, many scientists, philosophers, and physicians from around the world continued to contribute to the understanding of neuroanatomy, notably: Galen, Herophilus, Rhazes and Erasistratus. Herophilus and Erasistratus of Alexandria were perhaps the most influential Greek neuroscientists with their studies involving dissecting the brains.<ref name = RF/> For several hundred years afterward, with the cultural taboo of dissection, no major progress occurred in neuroscience. However, Pope Sixtus IV effectively revitalized the study of neuroanatomy by altering the papal policy and allowing human dissection. This resulted in a boom of research in neuroanatomy by artists and scientists of the Renaissance.<ref>Ginn, S. R., & Lorusso, L., "Brain, Mind, and Body: Interactions with Art in Renaissance Italy". Journal of the History of the Neurosciences, 2008, 17(3), 295-313.</ref>

In 1664, Thomas Willis, a physician and professor at Oxford University, coined the term neurology when he published his text Cerebri anatome which is considered the foundation of neuroanatomy.<ref>Neher, A., "Christopher Wren, Thomas Willis and the Depiction of the Brain and Nerves". Journal of Medical Humanities, 2009, 30(3), 191-200.</ref> The next four hundred some years has produced a great deal of documentation and study of the neural systems.

== Tools ==

Modern developments in neuroanatomy are directly correlated to the technologies used to perform research. Therefore it is necessary to discuss the various tools that are available.

Many of the [[histological]] techniques used to study other tissues can be applied to the nervous system as well. However, there are some techniques that have been developed especially for the study of neuroanatomy. Here are four examples:

1) The classic [[Golgi stain]] uses [[potassium dichromate]] and [[silver nitrate]] to stain neurons' [[dendrites]] and cell bodies in brown and black, allowing researchers to trace the paths of their thin processes in a slice of nervous tissue.

2) By expressing variable amounts of red, green, and blue fluorescent proteins in the brain, the so-called "[[brainbow]]" mutant mouse allows the combinatorial visualization of many different colors in neurons. This tags neurons with enough unique colors that they can often be distinguished from their neighbors with [[fluorescence microscopy]], enabling researchers to map the local connections between neurons.

3) [[Nissl staining]] uses dyes to intensely stain the [[rough endoplasmic reticulum]], which is abundant in neurons. This allows researchers to distinguish between different cell types (such as neurons and [[glia]]) in various regions of the nervous system.

4) [[Magnetic resonance imaging]] has been used extensively to investigate brain [[Diffusion tensor imaging|structure]] and [[Functional magnetic resonance imaging|function]] non-invasively in healthy human subjects.

The above is of course far from an exhaustive list, but it gives a sense of what type of tools can be used to probe the structure of the nervous system.

== Model systems ==

Aside from the [[human brain]], there are many other animals whose brains and nervous systems have received extensive study, including mice, [[zebrafish]]<ref>{{cite book |url=http://books.google.com/books?id=B5QVXvbOb1YC&pg=PA1&lpg=PA1&dq#v=onepage&q&f=false |title=Neuroanatomy of the zebrafish brain: a topological atlas |author= Wullimann, Mario F.; Rupp, Barbar;, Reichert, Heinrich|year=1996 |isbn=3764351209}}</ref>, [[Drosophila melanogaster|fruit fly]]<ref>http://web.neurobio.arizona.edu/Flybrain/html/index.html</ref>, and a species of roundworm called [[Caenorhabditis elegans|C. elegans]]. Each of these has its own advantages and disadvantages as a model system. For example, the C. elegans nervous system is extremely stereotyped from one individual worm to the next. This has allowed researchers using [[electron microscopy]] to map the paths and connections of all of the approximately 300 neurons in this species. The fruit fly is widely studied in part because its genetics is very well understood and easily manipulated. The mouse is used because, as a mammal, its brain is more similar in structure to our own (e.g., it has a six-layered [[Cerebral cortex|cortex]], yet its genes can be easily modified and its reproductive cycle is relatively fast.

== Composition ==

At the tissue level, the nervous system is composed of [[neurons]], [[glial cells]], and [[extracellular matrix]]. Both neurons and glial cells come in many types (see, for example, the nervous system section of the [[list of distinct cell types in the adult human body]]). Neurons are the information-processing cells of the nervous system: they sense our environment, communicate with each other via electrical signals and [[synapse|synapses]], and produce our thoughts and movements. Glial cells maintain homeostasis, produce [[myelin]], and provide support and protection for the brain's neurons. Some glial cells ([[astrocytes]]) can even propagate intercellular [[Astrocyte#Calcium waves|calcium waves]] over long distances in response to stimulation, and release [[gliotransmitters]] in response to changes in calcium concentration. The [[extracellular matrix]] also provides support on the molecular level for the brain's cells.

At the organ level, the nervous system is composed of brain regions, such as the [[hippocampus]] in mammals or the mushroom bodies of the [[Drosophila melanogaster|fruit fly]].<ref>http://web.neurobio.arizona.edu/Flybrain/html/atlas/structures/mushroom.html</ref> These regions are often modular and serve a particular role within the general pathways of the nervous system. For example, the hippocampus is critical for forming memories. The nervous system also contains [[nerves]], which are bundles of fibers that originate from the brain and spinal cord, and branch repeatedly to innervate every part of the body. Nerves are made primarily of the [[axons]] of neurons, along with a variety of membranes that wrap around and segregate them into [[nerve fascicles]].

The vertebrate nervous system is divided into the central and peripheral nervous systems. The [[central nervous system]] (CNS) consists of the [[human brain|brain]] and [[spinal cord]], while the [[peripheral nervous system]] (PNS) is made up of all the nerves outside of the CNS that connect it to the rest of the body. The PNS is further subdivided into the somatic and autonomic nervous systems. The [[somatic nervous system]] is made up of "afferent" neurons, which bring sensory information from the sense organs to the CNS, and "efferent" neurons, which carry motor instructions out to the muscles. The [[autonomic nervous system]] also has two subdivisions, the [[sympathetic nervous system|sympathetic]] and the [[parasympathetic nervous system|parasympathetic]], which are important for regulating the body's basic internal organ functions such as heartbeat, breathing, digestion, etc.

== Orientation in neuroanatomy ==
[[Image:Structural.gif|thumb|left|Para-sagittal [[MRI]] of the head in a patient with benign familial [[macrocephaly]].]]
In anatomy in general and neuroanatomy in particular, several sets of terms are used to denote orientation and location (see [[Anatomical terms of location]]). The pairs of terms used most commonly in neuroanatomy are:
* Dorsal and ventral: dorsal refers to the top or upper side, and ventral to the bottom or lower side.
* Rostral and caudal: rostral refers to the front (towards the nose; remember, "rostral" rhymes with "nostril"!), and caudal to the back (towards the tail).
* Medial and lateral: medial is towards the middle, and lateral is towards the side (away from the middle).

Commonly used terms for planes of orientation or planes of section in neuroanatomy are "transverse", "coronal", and "sagittal".
* A transverse plane is parallel to the ground, such that it divides the body or brain into a dorsal and a ventral portion.
* A sagittal plane divides the body or brain into left and right portions, and thus moves along the medial-lateral axis (see the image above).
* A coronal plane is parallel to the face, and thus divides the the body or brain into rostral (front) and caudal (back).

The directional terms "superior" and "inferior" and the "horizontal" plane are often used interchangeably with "dorsal", "ventral", and "transverse", and are equivalent in all animals other than humans. However, because humans walk on two legs, we have evolved a kink in our central nervous system, known as the [[cephalic flexure]], which bends the rostral part of the CNS at a 90 degree angle to the caudal part, at the level of the [[brainstem]]. Thus, confusion can arise when using these terms; for example, a coronal section of the [[forebrain]], say, just behind the eyes, is in a plane parallel to the face. But as it moves in the rostral direction, it rotates, such that a coronal section of the spinal cord is parallel to the ground. Similarly, one can say that the [[Cerebrum|forebrain]], the most rostral part of the CNS, is the most anterior part of the nervous system of a rat or a dog, but is the most superior part in a human.

==See also==
[[Neurology]]
[[Neuroscience]]

==References==
{{reflist}}

==External links==
{{commons category}}
*[http://www.neuroanatomy.org Neuroanatomy], an annual journal of clinical neuroanatomy
*[http://www.loni.ucla.edu/Atlases/ Mouse, Rat, Primate and Human Brain Atlases (UCLA Center for Computational Biology)]
*[http://brainmaps.org brainmaps.org: High-Resolution Neuroanatomically-Annotated Brain Atlases]
*[http://braininfo.rprc.washington.edu BrainInfo for Neuroanatomy]
*[http://www.sylvius.com High quality neuroanatomical visual glossary with several hundred entries]
*[http://www.stjudebgem.org/web/mainPage/mainPage.php Brain Gene Expression Map], mouse gene expression neuroanatomical resource from [[St. Jude Children's Research Hospital]]
*[http://brancusi.usc.edu/bkms/ Brain Architecture Management System], several atlases of brain anatomy
*[http://www.dtiatlas.org White Matter Atlas], Diffusion Tensor Imaging Atlas of the Brain's White Matter Tracts

{{Neuroscience}}

[[Category:Neuroanatomy| ]]
[[Category:Nervous system]]
[[Category:Neuroscience]]

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Cerebrum

2011-09-12T14:02:34Z

PhineasG: removed unnecessary "about"

{{Infobox Brain|
Name = Cerebrum |
Latin = |
GraySubject = |
GrayPage = |
Map --[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC)--[[Special:Contributions/203.100.1.66|203.100.1.66]] ([[User talk:203.100.1.66|talk]]) 01:04, 17 February 2010 (UTC) = Cerebrum map|
MapPos = |
MapCaption = The lobes of the cerebral cortex include the [[frontal lobe|frontal]] (blue), [[temporal lobe|temporal]] (green), [[occipital lobe|occipital]] (red), and [[parietal lobe]]s (yellow). The [[cerebellum]] (unlabeled) is not part of the telencephalon. |
Image2 = EmbryonicBrain.svg |
Caption2 = Diagram depicting the main subdivisions of the embryonic vertebrate brain. |
IsPartOf = |
Components = |
Artery = [[anterior cerebral artery|anterior cerebral]], [[middle cerebral artery|middle cerebral]], [[posterior cerebral artery|posterior cerebral]] |
Vein = [[cerebral veins]] |
BrainInfoType = |
BrainInfoNumber = |
MeshName = Telencephalon |
MeshNumber = A08.186.21.730.885 |
NeuroLex = Cerebrum
| NeuroLexID = birnlex_1042 |
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}}
The '''cerebrum''' or '''telencephalon''', together with the [[diencephalon]], constitute the [[forebrain]]. It is the most [[anterior]] or, especially in humans, most [[Anatomical terms of location#Superior and inferior|superior]] region of the [[vertebrate]] [[central nervous system]]. '''Telencephalon''' refers to the embryonic structure, from which the mature '''cerebrum''' develops. The [[Dorsum (biology)|dorsal]] telencephalon, or [[Pallium (neuroanatomy)|pallium]], develops into the [[cerebral cortex]], and the [[ventral]] telencephalon, or [[subpallium]], becomes the [[basal ganglia]]. The cerebrum is also divided into symmetric left and right cerebral hemispheres.

With the assistance of the [[cerebellum]], the cerebrum controls all voluntary actions in the body.

== Development ==
During vertebrate embryonic development, the [[prosencephalon]], the most anterior of three [[vesicle (biology)|vesicle]]s that form from the [[embryo]]nic [[neural tube]], is further subdivided into the telencephalon and [[diencephalon]]. The telencephalon then forms two lateral telencephalic vesicles which develop into the left and right cerebral hemisphere

==Hemispheres==
*left side controls right side of body
*right side controls left side of body

== Structure ==
The cerebrum is composed of the following sub-regions:
* [[Cerebral cortex]], or cortices of the cerebral hemispheres
* [[Basal ganglia]], or basal nuclei
* [[Limbic System]]

== Composition ==
[[File:Cerebrum animation small.gif|thumb|Location of the human cerebrum (red).]]
The cerebrum comprises what most people think of as the "[[brain]]." It lies in front or on top of the [[brainstem]] and in humans is the largest and most well-developed of the five major divisions of the brain. The cerebrum is the newest structure in the [[phylogenetic]] sense, with [[mammal]]s having the largest and most well-developed among all [[species]]. In larger mammals, the cerebral cortex is folded into many gyri and sulci, which has allowed the cortex to expand in surface area without taking up much greater volume.

In [[human]]s, the cerebrum surrounds older parts of the brain. [[Limbic]], [[olfactory]], and [[motor systems]] project fibers from the cerebrum to the [[brainstem]] and [[spinal cord]]. [[Cognition|Cognitive]] and [[volition (psychology)|volitive]] systems project fibers from the cerebrum to the [[thalamus]] and to specific regions of the [[midbrain]]. The neural networks of the cerebrum facilitate complex behaviors such as social interactions, thought, judgement, learning, [[working memory]], and in humans, speech and [[language]].

== Functions ==
'''Note''': As the cerebrum is a gross division with many subdivisions and sub-regions, it is important to state that this section lists the functions that the cerebrum ''as a whole'' serves. See main articles on [[cerebral cortex]] and [[basal ganglia]] for more information.

=== Movement ===
The cerebrum directs the conscious or volitional motor functions of the body. These functions originate within the [[primary motor cortex]] and other frontal lobe motor areas where actions are planned. [[Upper motor neuron]]s in the primary motor cortex send their [[axon]]s to the brainstem and spinal cord to [[synapse]] on the [[lower motor neurons]], which innervate the muscles. Damage to motor areas of cortex can lead to certain types of [[motor neuron disease]]. This kind of damage results in loss of muscular power and precision rather than total [[paralysis]].

=== Sensory processing ===
The primary sensory areas of the [[cerebral cortex]] receive and process visual, auditory, [[somatosensory]], [[gustatory]], and [[olfactory]] information. Together with association cortical areas, these brain regions synthesize sensory information into our perceptions of the world around us.

=== Olfaction ===
{{Main|Olfaction}}
The [[olfactory bulb]] in most vertebrates is the most anterior portion of the cerebrum, and makes up a relatively large proportion of the telencephalon. However, in humans, this part of the brain is much smaller, and lies underneath the frontal lobe. The olfactory sensory system is unique in the sense that neurons in the olfactory bulb send their axons directly to the [[piriform cortex|olfactory cortex]], rather than to the [[thalamus]] first. Damage to the olfactory bulb results in a loss of the sense of smell.

=== Language and communication ===
{{Main|Language}}
[[Speech communication|Speech]] and language are mainly attributed to parts of the cerebral cortex. Motor portions of language are attributed to [[Broca's area]] within the frontal lobe. Speech comprehension is attributed to [[Wernicke's area]], at the temporal-parietal lobe junction. These two regions are interconnected by a large [[white matter]] tract, the [[arcuate fasciculus]]. Damage to the Broca's area results in [[expressive aphasia]] (non-fluent aphasia) while damage to Wernicke's area results in [[receptive aphasia]] (also called fluent aphasia).

=== Learning and memory ===
{{Main|Memory}}
Explicit or declarative (factual) memory formation is attributed to the [[hippocampus]] and associated regions of the medial temporal lobe. This association was originally described after a patient known as [[HM (patient)|HM]] had both his hippocampuses (left and right) surgically removed to treat severe epilepsy. After surgery, HM had [[anterograde amnesia]], or the inability to form new memories.

Implicit or procedural memory, such as complex motor behaviors, involve the basal ganglia.

== Cell regeneration in ''Xenopus laevis'' ==
=== Larval stage ===
In a study of the telencephalon conducted in [[Hokkaido University]] on [[African clawed frog]]s (''Xenopus laevis''){{ref|Yoshino}}, it was discovered that, during [[larva]]l stages, the telencephalon was able to regenerate around half of the anterior portion (otherwise known as '''partially truncated'''), after a reconstruction of a would-be accident, or malformation of features.

The regeneration and active proliferation of cells within the clawed frog is quite remarkable, regenerated cells being almost functionally identical to the ones originally found in the brain after birth, despite the lack of brain matter for a sustained period of time.

This kind of regeneration depends on ependymal layer cells covering the cerebral lateral ventricles, within a short period before, or within the initial stage of wound-healing. This is observed within the stages of healing within larvae of the clawed frog.

=== Developed stage ===
The regeneration within the developed stage of the clawed frog is different from that in the larval stage. Because the cells adhere to one another, they are unable to form an entity that can cover the cerebral lateral ventricles. Thus, the telencephalon remains truncated and the loss of function becomes permanent.

=== Effects of abnormality ===
After removing over half of the telencephalon in the developed stage of the clawed frog, the lack of functions within the animal was apparent, manifesting with obvious difficulties in movement, [[nonverbal communication]] between other species, as well as other difficulties thought to be similar to those seen in humans.

This kind of regeneration is still relatively unknown in regard to regeneration within larval stages, similar to the human [[fetus|fetal stage]].

==Variation among species==
In the most primitive living vertebrates, the [[hagfish]]es and [[lamprey]]s, the cerebrum is a relatively simple structure receiving nerve impulses from the [[olfactory bulb]]. In [[cartilaginous]] and [[lobe-finned fish]]es, and also in [[amphibian]]s, a more complex structure is present, with the cerebrum being divided into three distinct regions. The lowermost (or ventral) region forms the basal nuclei, and contains fibres connecting the rest of the cerebrum to the [[thalamus]]. Above this, and forming the lateral part of the cerebrum, is the ''paleopallium'', while the uppermost (or dorsal) part is referred to as the ''archipallium''. The cerebrum remains largely devoted to olfactory sensation in these animals, despite its much wider range of functions in [[amniote]]s.{{ref|VB}}

In [[ray-finned fish]]es, the structure is somewhat different. The inner surfaces of the lateral and ventral regions of the cerebrum bulge up into the ventricles; these include both the basal nuclei and the various parts of the pallium, and may be complex in structure, especially in [[teleost]]s. The dorsal surface of the cerebrum is membranous, and does not contain any nervous tissue.{{ref|VB}}

In the amniotes, the cerebrum becomes increasingly large and complex. In [[reptile]]s, the paleopallium is much larger than in amphibians, and its growth has pushed the basal nuclei into the central regions of the cerebrum. As in the lower vertebrates, the grey matter is generally located beneath the white matter, but in some reptiles, it spreads out to the surface to form a primitive cortex, especially in the anterior part of the brain.{{ref|VB}}

In [[mammal]]s, this development proceeds further, so that the cortex covers almost the whole of the cerebral hemispheres, especially in more "advanced" species, such as [[primate]]s. The paleopallium is pushed to the ventral surface of the brain, where it becomes the olfactory lobes, while the archipallium becomes rolled over at the medial dorsal edge to form the [[hippocampus]]. In [[placental mammal]]s, a [[corpus callosum]] also develops, further connecting the two hemispheres. The complex convolutions of the cerebral surface are also found only in higher mammals.{{ref|VB}}

The cerebrum of [[bird]]s has evolved along different lines to that of mammals, although they are similarly enlarged, by comparison with reptiles. However, this enlargement is largely due to the basal ganglia, with the other areas remaining relatively primitive in structure. For example, there is no great expansion of the cerebral cortex, as there is in mammals. Instead, an [[High vocal center|HVC]] develops just above the basal ganglia, and this appears to be the area of the bird brain most concerned with learning complex tasks.{{ref|VB}}

== See also==
* [[List of regions in the human brain]]
* [[Cerebral cortex]]
* [[Basal ganglia]]

== References ==
#{{note|Levi-Oppenheim}} Levi-Montalcini, R. (1949). Proliferation, differentiation and degeneration in the spinal ganglia of the chick embryo under normal and experimental conditions. Pages 450–502.
#{{note|Yoshino}} Yoshino J, Tochinai S. Successful reconstitution of the non-regenerating adult telencephalon by cell transplantation in Xenopus laevis. ''Dev Growth Differ.'' 2004;46(6):523–34. PMID 15610142.
#{{note|Yaginuma}} Yaginuma, H., Tomita, M., Takashita, N., McKay, S., Cardwell, C., Yin, Q. Aminobuytric acid immunoreactivity within the human cerebral cortex. Pages 481–500.
#{{note|Haydar}} Haydar, T. F, Kuan, C., Y., Flavell, R. A. & Rakic, P. (1999) The role of cell death in regulating the size and shape of the mammalian forebrain. Pages 621–626.
#{{note|VB}} {{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 536–543|isbn= 0-03-910284-X}}

==External links==
* [http://www.rahulgladwin.com/blog/2006/06/cerebrum-higher-integrative-functions.html Cerebrum Medical Notes on rahulgladwin.com]
* [http://www.neuinfo.org/nif/nifgwt.html?query=%22Cerebrum%22 NIF Search - Cerebrum] via the [[Neuroscience Information Framework]]

{{Nervous system}}
{{Cerebral cortex}}
{{Commissural fibers}}
{{Lateral ventricles}}
{{Rostral basal ganglia and associated structures}}
{{Association fibers}}

[[Category:Cerebrum| ]]

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Brodmann area

2011-09-09T20:04:00Z

PhineasG: /* History */

[[Image:Brodmann areas 3D.png|thumb|Brodmann areas 3D]]
[[Image:Gray726-Brodman.png|thumb|Lateral surface of the brain with Brodmann's areas numbered.]]
[[Image:Gray727-Brodman.png|thumb|Medial surface of the brain with Brodmann's areas numbered.]]
A '''Brodmann area''' is a region of the [[cerebral cortex]] defined based on its [[cytoarchitectonics of the cerebral cortex|cytoarchitectonics]], or organization of cells.

==History==
Brodmann areas were originally defined and numbered by the [[Germans|German]] [[anatomist]] [[Korbinian Brodmann]] based on the [[cytoarchitecture|cytoarchitectural]] organization of [[neuron]]s he observed in the cerebral cortex using the [[Franz Nissl|Nissl]] [[staining|stain]]. Brodmann published his maps of cortical areas in humans, monkeys, and other species in 1909<ref>Brodmann K. Vergleichende Lokalisationslehre der Grosshirnrinde. Leipzig : Johann Ambrosius Bart, 1909</ref>, along with many other findings and observations regarding the general cell types and [[Cerebral cortex#Laminar pattern|laminar organization]] of the mammalian cortex. (The same Brodmann area number in different species does not necessarily indicate homologous areas<ref>Garey LJ. Brodmann's Localisation in the Cerebral Cortex. New York : Springer, 2006 (ISBN 0-387-26917-7) (ISBN 978-0387-26917-7)</ref>.) A similar, but more detailed cortical map was published by [[Constantin von Economo]] and [[Georg N. Koskinas]] in 1925<ref name=" Economo, C., Koskinas, G.N. (1925).">'' Economo, C., Koskinas, G.N. (1925). '' Die Cytoarchitektonik der Hirnrinde des erwachsenen Menschen. Wien: Springer Verlag.</ref>.

==Present importance==
Brodmann areas have been discussed, debated, refined, and renamed exhaustively for nearly a century and remain the most widely known and frequently cited cytoarchitectural organization of the human cortex.

Many of the areas Brodmann defined based solely on their neuronal organization have since been correlated closely to diverse cortical functions. For example, Brodmann areas 1, 2 and 3 are the [[primary somatosensory cortex]]; area 4 is the [[primary motor cortex]]; area 17 is the [[primary visual cortex]]; and areas 41 and 42 correspond closely to [[primary auditory cortex]]. Higher order functions of the [[Cerebral cortex#Association areas|association cortical areas]] are also consistently localized to the same Brodmann areas by [[neurophysiology|neurophysiological]], [[Functional magnetic resonance imaging|functional imaging]], and other methods (e.g., the consistent localization of [[Broca's area|Broca's]] speech and language area to the left Brodmann areas 44 and 45). However, functional imaging can only identify the approximate localization of brain activations in terms of Brodmann areas since their actual boundaries in any individual brain requires its [[histological]] examination.

==Brodmann areas for human & non-human primates ==

* [[Brodmann areas 3, 1 and 2|Areas 3, 1 & 2 - Primary Somatosensory Cortex]] (frequently referred to as Areas 3, 1, 2 by convention)
* [[Brodmann area 4|Area 4 - Primary Motor Cortex]]
* [[Brodmann area 5|Area 5 - Somatosensory Association Cortex]]
* [[Brodmann area 6|Area 6]] - [[Premotor cortex]] and Supplementary Motor Cortex (Secondary Motor Cortex)([[Supplementary motor area]])
* [[Brodmann area 7|Area 7 - Somatosensory Association Cortex]]
* [[Brodmann area 8|Area 8]] - Includes [[Frontal eye fields]]
* [[Brodmann area 9|Area 9]] - [[Dorsolateral prefrontal cortex]]
* [[Brodmann area 10|Area 10]] - [[Anterior prefrontal cortex]] (most rostral part of superior and middle frontal gyri)
* [[Brodmann area 11|Area 11]] - [[Orbitofrontal cortex|Orbitofrontal area]] (orbital and rectus gyri, plus part of the rostral part of the superior frontal gyrus)
* [[Brodmann area 12|Area 12]] - [[Orbitofrontal cortex|Orbitofrontal area]] (used to be part of BA11, refers to the area between the superior frontal gyrus and the inferior rostral sulcus)
* [[Brodmann area 13|Area 13]] and [[Brodmann area 14|Area 14]]* - [[Insular cortex]]
* [[Brodmann area 15|Area 15]]* - Anterior Temporal Lobe
* [[Brodmann area 17|Area 17]] - [[Visual_cortex#V1|Primary visual cortex (V1)]]
* [[Brodmann area 18|Area 18]] - [[Visual_cortex#V2|Secondary visual cortex (V2)]]
* [[Brodmann area 19|Area 19]] - [[Visual_cortex#V3|Associative visual cortex (V3)]]
* [[Brodmann area 20|Area 20]] - [[Inferior temporal gyrus]]
* [[Brodmann area 21|Area 21]] - [[Middle temporal gyrus]]
* [[Brodmann area 22|Area 22]] - [[Superior temporal gyrus]], of which the caudal part is usually considered to contain the [[Wernicke's area]]
* [[Brodmann area 23|Area 23]] - Ventral [[Posterior cingulate cortex]]
* [[Brodmann area 24|Area 24]] - Ventral [[Anterior cingulate cortex]].
* [[Brodmann area 25|Area 25]] - Subgenual cortex (part of the [[Ventromedial_prefrontal_cortex|Ventromedial prefontal cortex]])<ref>http://ukpmc.ac.uk/articles/PMC2268639;jsessionid=BBF4DB8DAFCFCB452BEA9AB7368AB5C6.jvm4</ref>
* [[Brodmann area 26|Area 26]] - [[Ectosplenial_area_26|Ectosplenial]] portion of the retrosplenial region of the cerebral cortex
* [[Brodmann area 27|Area 27]] - [[Piriform cortex]]
* [[Brodmann area 28|Area 28]] - Posterior [[Entorhinal Cortex]]
* [[Brodmann area 29|Area 29]] - Retrosplenial [[cingulate cortex]]
* [[Brodmann area 30|Area 30]] - Part of [[cingulate cortex]]
* [[Brodmann area 31|Area 31]] - Dorsal [[Posterior cingulate cortex]]
* [[Brodmann area 32|Area 32]] - Dorsal [[anterior cingulate cortex]]
* [[Brodmann area 33|Area 33]] - Part of [[anterior cingulate cortex]]
* [[Brodmann area 34|Area 34]] - Anterior [[Entorhinal Cortex]] (on the [[Parahippocampal gyrus]])
* [[Brodmann area 35|Area 35]] - [[Perirhinal cortex]] (on the [[Parahippocampal gyrus]])
* [[Brodmann area 36|Area 36]] - [[Parahippocampal cortex]] (on the [[Parahippocampal gyrus]])
* [[Brodmann area 37|Area 37]] - [[Fusiform gyrus]]
* [[Brodmann area 38|Area 38]] - [[Brodmann_area_38|Temporopolar]] area (most rostral part of the superior and middle temporal gyri)
* [[Brodmann area 39|Area 39]] - [[Angular gyrus]], considered by some to be part of [[Wernicke's area]]
* [[Brodmann area 40|Area 40]] - [[Supramarginal gyrus]] considered by some to be part of [[Wernicke's area]]
* [[Brodmann area 41 & 42|Areas 41 & 42 - Primary and Auditory Association Cortex]]
* [[Brodmann area 43|Area 43]] - Primary gustatory cortex
* [[Brodmann area 44|Area 44]] - [[pars opercularis]], part of [[Broca's area]]
* [[Brodmann area 45|Area 45]] - [[pars triangularis]] [[Broca's area]]
* [[Brodmann area 46|Area 46]] - [[Dorsolateral prefrontal cortex]]
* [[Brodmann area 47|Area 47]] - [[Inferior_frontal_gyrus|Inferior prefontal gyrus]]
* [[Brodmann area 48|Area 48]] - [[Brodmann_area_48|Retrosubicular area]] (a small part of the medial surface of the temporal lobe)
* [[Brodmann area 49|Area 49]] - [[Parasubiculum]] area in a rodent
* [[Brodmann area 52|Area 52]] - [[Parainsular_area_52|Parainsular]] area (at the junction of the temporal lobe and the [[Insular cortex|insula]])
(*) Area only found in non-human [[primate]]s.

Some of the original Brodmann areas have been subdivided further, e.g., "23a" and "23b".<ref>{{Cite journal
| author = Brent A. Vogt, [[Deepak Pandya|Deepak N. Pandya]], Douglas L. Rosene
| title = Cingulate cortex of the rhesus monkey: I. Cytoarchitecture and thalamic afferents
| journal = The Journal of Comparative Neurology
| volume = 262
| issue = 2
| pages = 256–270
| month = August
| year = 1987
| doi = 10.1002/cne.902620207
| pmid = 3624554
}}</ref>

=== Clickable map: Lateral Surface ===
<imagemap>
Image:Gray726-Brodman.png|Image mapped [[Brodmann Areas]]. Clicking on an area in the picture causes the browser to load the appropriate article.|480px
rect 509 186 596 236 [[Brodmann areas 3, 1 and 2|Areas 3, 1 & 2 - Primary Somatosensory Cortex]]
rect 474 122 524 172 [[Brodmann area 4|Area 4 - Primary Motor Cortex]]
rect 602 143 652 193 [[Brodmann area 5|Area 5 - Somatosensory Association Cortex]]
rect 378 162 428 212 [[Brodmann area 6|Area 6 - Premotor cortex and Supplementary Motor Cortex (Secondary Motor Cortex)(Supplementary motor area]]
rect 692 178 742 228 [[Brodmann area 7|Area 7 - Somatosensory Association Cortex]]
rect 259 107 309 157 [[Brodmann area 8|Area 8 - Includes Frontal eye fields]]
rect 137 162 188 212 [[Brodmann area 9|Area 9- Dorsolateral prefrontal cortex]]
rect 31 330 81 380 [[Brodmann area 10|Area 10 - Anterior prefrontal cortex]]
rect 65 427 116 477 [[Brodmann area 11|Area 11 - Orbitofrontal area]]
rect 892 459 942 509 [[Brodmann area 17|Area 17 - Primary visual cortex (V1)]]
rect 834 427 885 477 [[Brodmann area 18|Area 18 - Secondary visual cortex (V2)]]
rect 770 385 821 435 [[Brodmann area 19|Area 19 - Associative visual cortex (V3)]]
rect 427 554 477 604 [[Brodmann area 20|Area 20 - Inferior temporal gyrus]]
rect 474 491 524 541 [[Brodmann area 21|Area 21 - Middle temporal gyrus]]
rect 635 417 686 467 [[Brodmann area 22|Area 22 - Superior temporal gyrus]]

rect 673 484 723 534 [[Brodmann area 37|Area 37 - Fusiform gyrus]]
rect 250 505 301 555 [[Brodmann area 38|Area 38 - Temporopolar area]]
rect 706 307 757 357 [[Brodmann area 39|Area 39 - Angular gyrus]]
rect 571 315 622 365 [[Brodmann area 40|Area 40 - Supramarginal gyrus]]
rect 536 394 587 444 [[Brodmann area 41 & 42|Area 41- Primary and Auditory Association Cortex]]
rect 589 411 634 461 [[Brodmann area 41 & 42|Area 42 - Primary and Auditory Association Cortex]]
rect 416 368 467 418 [[Brodmann area 43|Area 43 - Primary gustatory cortex]]
rect 282 353 333 403 [[Brodmann area 44|Area 44 - pars opercularis, part of Broca's area]]
rect 219 378 270 428 [[Brodmann area 45|Area 45 - pars triangularis, Broca's area]]
rect 144 257 195 307 [[Brodmann area 46|Area 46 - Dorsolateral prefrontal cortex]]
rect 145 410 196 460 [[Brodmann area 47|Area 47 - Inferior prefontal gyrus]]
rect 958 718 960 720 [http://www.image-maps.com/index.php?aff=mapped_users_4201105031226273 Image Map]
desc bottom-left
</imagemap>

=== Clickable map: Medial Surface ===

<imagemap>
Image:Gray727-Brodman.png|Image mapped [[Brodmann Areas]]. Clicking on an area in the picture causes the browser to load the appropriate article.|480px
rect 509 186 596 236 [[Brodmann areas 3, 1 and 2|Areas 3, 1 & 2 - Primary Somatosensory Cortex]]
rect 442 99 492 149 [[brodmann area 4|area 4 - primary motor cortex]]
rect 538 162 588 212 [[Brodmann area 5|Area 5 - Somatosensory Association Cortex]]
rect 306 122 356 172 [[Brodmann area 6|Area 6 - Premotor cortex and Supplementary Motor Cortex (Secondary Motor Cortex)(Supplementary motor area]]
rect 714 155 764 205 [[Brodmann area 7|Area 7 - Somatosensory Association Cortex]]
rect 193 155 243 205 [[Brodmann area 8|Area 8 - Includes Frontal eye fields]]
rect 106 211 156 261 [[Brodmann area 9|Area 9- Dorsolateral prefrontal cortex]]
rect 35 323 85 373 [[Brodmann area 10|Area 10 - Anterior prefrontal cortex]]
rect 74 441 124 491 [[Brodmann area 11|Area 11 - Orbitofrontal area]]
rect 162 404 212 454 [[Brodmann area 12|Area 12 -Orbitofrontal area]]
rect 819 378 869 428 [[Brodmann area 17|Area 17 - Primary visual cortex (V1)]]
rect 761 428 811 478 [[Brodmann area 18|Area 18 - Secondary visual cortex (V2)]]
rect 697 467 747 517 [[Brodmann area 19|Area 19 - Associative visual cortex (V3)]]
rect 810 233 860 283 [[Brodmann area 19|Area 19 - Associative visual cortex (V3)]]
rect 860 308 910 358 [[Brodmann area 18|Area 18 - Secondary visual cortex (V2)]]
rect 563 289 613 339 [[Brodmann area 23|Area 23 - Ventral Posterior cingulate cortex]]
rect 314 210 364 260 [[Brodmann area 24|Area 24 - Ventral Anterior cingulate cortex]]
rect 227 434 277 484 [[Brodmann area 25|Area 25 - Subgenual cortex (part of the Ventromedial prefontal cortex)]]
rect 512 355 562 405 [[Brodmann area 26|Area 26 - Ectosplenial portion of the retrosplenial region of the cerebral cortex]]
rect 377 448 427 498 [[Brodmann area 27|Area 27 - Piriform cortex]]
rect 314 489 364 539 [[Brodmann area 28|Area 28 - Posterior Entorhinal Cortex]]
rect 571 371 621 421 [[Brodmann area 29|Area 29 - Retrosplenial cingulate cortex]]
rect 532 419 582 469 [[Brodmann area 30|Area 30 - Part of cingulate cortex]]
rect 632 264 682 314 [[Brodmann area 31|Area 31 - Dorsal Posterior cingulate cortex]]
rect 138 330 188 380 [[Brodmann area 32|Area 32 - Dorsal anterior cingulate cortex]]
rect 234 290 284 340 [[Brodmann area 33|Area 33 - Part of anterior cingulate cortex]]
rect 305 435 355 485 [[Brodmann area 34|Area 34 - Anterior Entorhinal Cortex (on the Parahippocampal gyrus)]]
rect 448 450 498 500 [[Brodmann area 35|Area 35 - Perirhinal cortex (on the Parahippocampal gyrus)]]
rect 448 507 498 557 [[Brodmann area 20|Area 20 - Inferior temporal gyrus]]
rect 585 482 635 532 [[Brodmann area 37|Area 37 - Fusiform gyrus]]
rect 559 100 648 150 [[Brodmann areas 3, 1 and 2|Areas 3, 1 & 2 - Primary Somatosensory Cortex]]
rect 265 532 318 582 [[Brodmann area 38|Area 38 - Temporopolar area]]
rect 958 718 960 720 [http://www.image-maps.com/index.php?aff=mapped_users_1201105031640502 Image Map]
desc bottom-left
</imagemap>

== Criticism ==
When von Bonin and Bailey constructed a brain map for the [[macaque]] monkey they found the description of Brodmann inadequate and wrote:
: ''Brodmann (1907), it is true, prepared a map of the human brain which has been widely reproduced, but, unfortunately, the data on which it was based was never published''<ref>{{Cite book
| author = Gerhardt von Bonin & Percival Bailey
| title = The Neocortex of Macaca Mulatta
| publisher = The [[University of Illinois]] Press
| location = [[Urbana, Illinois|Urbana]], [[Illinois]]
| year = 1925
}}</ref>
They instead used the cytoarchitechtonic scheme of [[Constantin von Economo]] and [[Georg N. Koskinas]] published in 1925<ref>{{Cite book
| author = [[Constantin von Economo]] & [[Georg N. Koskinas]]
| title = Die Cytoarchitektonik der Hirnrinde des erwachsenen Menschen
| publisher = [[Julius Springer]]
| year = 1925
| location = Vienna and Berlin
}}</ref>
which had the "only acceptable detailed description of the human cortex".

== See also ==
* [[Brain]]
* [[Cortical area]]
* [[List of regions in the human brain]]

== References ==
{{Refimprove|date=November 2007}}
{{reflist}}

== External links ==
{{Commons|Brodmann areas}}
* [http://www.trincoll.edu/~dlloyd/brodmann.html brodmann x func] — Functional categorization of Brodmann areas.
* [http://spot.colorado.edu/~dubin/talks/brodmann/brodmann.html Brodmann], Mark Dubin pages on Brodmann areas.
* [http://braininfo.rprc.washington.edu/scripts/indexotheratlas.aspx?othersiteID= Brodmann areas of cortex involved in language]

{{Telencephalon}}

{{DEFAULTSORT:Brodmann Area}}
[[Category:Brodmann areas| ]]
[[Category:Cerebrum]]
[[Category:Cognitive neuroscience]]

[[ca:Àrees de Brodmann]]
[[de:Brodmann-Areal]]
[[es:Áreas de Brodmann]]
[[fr:Aires de Brodmann]]
[[ko:브로드만]]
[[id:Area Brodmann]]
[[it:Aree di Brodmann]]
[[nl:Gebied van Brodmann]]
[[ja:ブロードマンの脳地図]]
[[pl:Pola Brodmanna]]
[[ru:Цитоархитектонические поля Бродмана]]
[[fi:Brodmannin alue]]
[[sv:Brodmannarea]]
[[zh:Brodmann分区系统]]

Brain development timelines

2011-09-07T18:24:18Z

PhineasG: added See Also: translatingtime.net

These are timelines of brain development events in different species.

*[[Mouse brain development timeline]]
*[[Macaque brain development timeline]]
*[[Human brain development timeline]]

==See also==
[[Neural development]]

==External links==
* ''[http://www.translatingtime.net/ Translating Neurodevelopmental Time Across Mammalian Species]''

[[Category:Developmental biology]]
[[Category:Embryology of nervous system]]
[[Category:Developmental neuroscience]]

{{neuroscience-stub}}

Development of the nervous system

2011-09-07T18:22:51Z

PhineasG: /* External links */

'''Neural development''' comprises the processes that generate, shape, and reshape the nervous system, from the earliest stages of embryogenesis to the final years of life. The study of neural development aims to describe the cellular basis of [[brain]] development and to address the underlying mechanisms. The field draws on both [[neuroscience]] and [[developmental biology]] to provide insight into the cellular and molecular mechanisms by which complex [[nervous system]]s develop. Defects in neural development can lead to cognitive, motor, and intellectual disability, as well as [[neurological disorders]] such as [[autism]], [[Rett syndrome]], and [[mental retardation]].

==Overview of brain development==
The brain emerges during embryonic development from the neural tube, an early embryonic structure. The most anterior part of the neural tube is called the telencephalon, which expands rapidly due to cell proliferation, and eventually gives rise to the brain. Gradually some of the cells stop dividing and differentiate into [[neurons]] and [[glial cells]], which are the main cellular components of the brain. The newly generated neurons migrate to different parts of the developing brain to self-organize into different brain structures. Once the neurons have reached their regional positions, they extend [[axons]] and [[dendrites]], which allow them to communicate with other neurons via [[synapses]]. Synaptic communication between neurons leads to the establishment of functional neural circuits that mediate sensory and motor processing, and underlie behavior. The brain does most of its development within the first 20 years of life.

[[Image:development of nervous system.svg|thumbnail|750px|center|Highly schematic flowchart of human brain development.]]

==Aspects of neural development==
Some landmarks of neural development include the birth and [[cellular differentiation|differentiation]] of [[neuron]]s from [[stem cells|stem cell]] precursors, the [[cellular migration|migration]] of immature neurons from their birthplaces in the embryo to their final positions, outgrowth of [[axon]]s and [[dendrite]]s from neurons, [[axon guidance|guidance]] of the motile [[growth cone]] through the embryo towards postsynaptic partners, the generation of [[synapse]]s between these axons and their postsynaptic partners, and finally the lifelong [[synaptic plasticity|changes]] in synapses, which are thought to underlie learning and memory.

Typically, these neurodevelopmental processes can be broadly divided into two classes: activity-independent mechanisms and activity-dependent mechanisms. Activity-independent mechanisms are generally believed to occur as hardwired processes determined by genetic programs played out within individual neurons. These include [[cellular differentiation|differentiation]], [[cellular migration|migration]] and [[axon guidance]] to their initial target areas. These processes are thought of as being independent of neural activity and sensory experience. Once [[axon]]s reach their target areas, activity-dependent mechanisms come into play. Although synapse formation is an activity-independent event, modification of synapses and synapse elimination requires neural activity.

Developmental neuroscience uses a variety of animal models including mice ''[[Mus musculus]]'' , the fruit fly ''[[Drosophila melanogaster]]'' , the zebrafish ''[[Danio rerio]]'', ''[[Xenopus laevis]]'' tadpoles and the worm ''[[Caenorhabditis elegans]]'', among others.

==Neural induction==
During early embryonic development the ectoderm becomes specified to give rise to the epidermis (skin) and the neural plate. The conversion of undifferentiated ectoderm to neuro-ectoderm requires signals from the mesoderm. At the onset of gastrulation presumptive mesodermal cells move through the dorsal blastopore lip and form a layer in between the endoderm and the ectoderm. These mesodermal cells that migrate along the dorsal midline give rise to a structure called the notochord. Ectodermal cells overlying the notochord develop into the neural plate in response to a diffusible signal produced by the notochord. The remainder of the ectoderm gives rise to the epidermis (skin). The ability of the mesoderm to convert the overlying ectoderm into neural tissue is called '''Neural Induction'''.

The neural plate folds outwards during the third week of gestation to form the [[neural groove]]. Beginning in the future neck region, the [[neural folds]] of this groove close to create the [[neural tube]]. The formation of the neural tube from the ectoderm is called '''Neurulation'''. The ventral part of the neural tube is called the [[basal plate]]; the dorsal part is called the [[alar plate]]. The hollow interior is called the [[neural canal]]. By the end of the fourth week of gestation, the open ends of the neural tube (the '''neuropores''') close off.<ref>{{cite book |author=Estomih Mtui; Gregory Gruener |title=Clinical Neuroanatomy and Neuroscience |publisher=Saunders |location=Philadelphia |pages=1 |year=2006 |isbn=1-4160-3445-5 }}</ref>

'''Identification of neural inducers'''

A transplanted blastopore lip can convert ectoderm into neural tissue and is said to have an inductive effect. Neural Inducers are molecules that can induce the expression of neural genes in ectoderm explants without inducing mesodermal genes as well. Neural induction is often studied in Xenopus embryos since they have a simple body pattern and there are good markers to distinguish between neural and non-neural tissue. Examples of Neural Inducers are the molecules Noggin and Chordin.

When embryonic ectodermal cells are cultured at low density in the absence of mesodermal cells they undergo neural differentiation (express neural genes), suggesting that neural differentiation is the default fate of ectodermal cells. In explant cultures (which allow direct cell-cell interactions) the same cells differentiate into epidermis. This is due to the action of BMP4 (a TGF-β family protein) that induces ectodermal cultures to differentiate into epidermis. During neural induction, Noggin and Chordin are produced by the dorsal mesoderm (notochord) and diffuse into the overlying ectoderm to inhibit the activity of BMP4. This inhibition of BMP4 causes the cells to differentiate into neural cells.

==Regionalization==

Late in the fourth week, the superior part of the neural tube flexes at the level of the future midbrain—the [[mesencephalon]]. Above the [[mesencephalon]] is the [[prosencephalon]] (future forebrain) and beneath it is the [[rhombencephalon]] (future hindbrain).

The [[optical vesicle]] (which will eventually become the optic nerve, retina and iris) forms at the basal plate of the prosencephalon. The alar plate of the prosencephalon expands to form the cerebral hemispheres (the [[telencephalon]]) whilst its basal plate becomes the [[diencephalon]]. Finally, the optic vesicle grows to form an optic outgrowth.

==Patterning of the nervous system==
In [[chordates]], dorsal ectoderm forms all neural tissue and the nervous system. Patterning occurs due to specific environmental conditions - different concentrations of signaling molecules

'''Dorsoventral axis'''
<ref>{{cite book |author=Jessell, Thomas M.; Kandel, Eric R.; Schwartz, James H. |title=Principles of neural science |publisher=McGraw-Hill |location=New York |year=2000 |pages= |isbn=0-8385-7701-6 |edition=4th |chapter=Chapter 55}}</ref>

The ventral half of the [[neural plate]] is controlled by the [[notochord]], which acts as the 'organiser'. The dorsal half is controlled by the [[ectoderm]] plate which flanks the neural plate on either side.

Ectoderm follows a default pathway to become neural tissue. Evidence for this comes from single, cultured cells of ectoderm which go on to form neural tissue. This is postulated to be because of a lack of [[BMP]]s, which are blocked by the organiser. The organiser may produce molecules such as [[follistatin]], [[noggin]] and [[chordin]] which inhibit BMPs.

The ventral neural tube is patterned by [[Sonic Hedgehog]] (Shh) from the notochord, which acts as the inducing tissue. The Shh inducer causes differentiation of the floor plate. Shh-null tissue fails to generate all cell types in the ventral tube, suggesting Shh is necessary for its induction. The hypothesised mechanism suggests that Shh binds [[patched]], relieving patched inhibition of [[smoothened]], leading to activation of [[glia]] [[transcription factors]].

In this context Shh acts as a [[morphogen]] - it induces cell differentiation dependent on its concentration. At low concentrations it forms ventral interneurones, at higher concentrations it induces motor neurone development, and at highest concentrations it induces floor plate differentiation. Failure of Shh-modulated differentiation causes holoprosencephaly.

The dorsal neural tube is patterned by BMPs from the epidermal ectoderm flanking the neural plate. These induce sensory interneurones by activating Sr/Thr kinases and altering [[SMAD]] transcription factor levels.

'''Rostrocaudal (Anteroposterior) axis'''

Signals that control anteroposterior neural development include FGF and [[retinoic acid]] which act in the hindbrain and spinal cord.<ref name="Duester">{{cite journal |last1=Duester |first1=G |title=Retinoic acid synthesis and signaling during early organogenesis |journal=Cell |volume=134 |issue=6 |pages=921–31 |year=2008 |month=September |pmid=18805086 |pmc=2632951 |doi=10.1016/j.cell.2008.09.002 }}</ref> The hindbrain, for example, is patterned by [[Hox genes]], which are expressed in overlapping domains along the anteroposterior axis under the control of retinoic acid. The 3' genes in the Hox cluster are induced by retinoic acid in the hindbrain, whereas the 5' Hox genes are not induced by retinoic acid and are expressed more posteriorly in the spinal cord. Hoxb-1 is expressed in rhombomere 4 and gives rise to the [[facial nerve]]. Without this Hoxb-1 expression, a nerve which is similar to the [[trigeminal nerve]] arises.

===Neuronal migration=== 
[[Image:Corticogenesis in a wild-type mouse.gif|thumb|Corticogenesis: younger neurons migrate past older ones using [[radial glia]] as a scaffolding. [[Cajal-Retzius cell]]s (red) release [[reelin]] (orange).]]
Neuronal [[Cellular migration|migration]] is the method by which neurons travel from their origin or birth place to their final position in the brain. There are several ways they can do this, e.g. by radial migration or tangential migration. (see [http://www.nature.com/neuro/journal/v4/n2/extref/nn0201-143-S1.mpg time lapse] sequences of radial migration (also known as glial guidance) and somal translocation.)<ref name=Nadar1>{{cite journal |author=Nadarajah B, Brunstrom J, Grutzendler J, Wong R, Pearlman A |title=Two modes of radial migration in early development of the cerebral cortex |journal=Nat Neurosci |volume=4 |issue=2 |pages=143–50 |year=2001 |pmid=11175874 |doi=10.1038/83967 |url=http://www.nature.com/neuro/journal/v4/n2/full/nn0201_143.html}}</ref>

[[File:Interneuron-radial glial interactions in the developing cerebral cortex.png|thumb|Tangential migration of interneurons from [[ganglionic eminence]].]]

'''Radial migration'''
Neuronal precursor cells proliferate in the ventricular zone of the developing [[neocortex]]. The first [[mitosis|postmitotic]] cells to migrate form the preplate which are destined to become [[Cajal-Retzius cells]] and [[subplate]] neurons. These cells do so by somal translocation. Neurons migrating with this mode of locomotion are bipolar and attach the leading edge of the process to the [[pia mater|pia]]. The [[soma (biology)|soma]] is then transported to the pial surface by [[nucleokinesis]], a process by which a [[microtubules|microtubule]] "cage" around the nucleus elongates and contracts in association with the [[centrosome]] to guide the nucleus to its final destination.<ref>{{cite journal |author=Samuels B, Tsai L |title=Nucleokinesis illuminated |journal=Nat Neurosci |volume=7 |issue=11 |pages=1169–70 |year=2004 |pmid=15508010 |doi=10.1038/nn1104-1169 |url=http://www.nature.com/neuro/journal/v7/n11/full/nn1104-1169.html}}</ref> Radial glia, whose fibers serve as a scaffolding for migrating cells, can itself divide<ref name=pmid11535293>{{cite journal |author=Tamamaki N, Nakamura K, Okamoto K, Kaneko T |title=Radial glia is a progenitor of neocortical neurons in the developing cerebral cortex |journal=[[Neurosci. Res.]] |volume=41 |issue=1 |pages=51–60 |year=2001 |month= September|pmid=11535293 |doi= 10.1016/S0168-0102(01)00259-0|url=http://linkinghub.elsevier.com/retrieve/pii/S0168010201002590}}</ref> or translocate to the cortical plate and differentiate either into [[astrocyte]]s or [[neuron]]s.<ref name=pmid11567613>{{cite journal |author=Miyata T, Kawaguchi A, Okano H, Ogawa M |title=Asymmetric inheritance of radial glial fibers by cortical neurons |journal=[[Neuron (journal)|Neuron]] |volume=31 |issue=5 |pages=727–41 |year=2001 |month= September|pmid=11567613 |doi= 10.1016/S0896-6273(01)00420-2|url=http://linkinghub.elsevier.com/retrieve/pii/S0896-6273(01)00420-2}}</ref> Somal translocation can occur at any time during development.<ref name=Nadar1/>

Subsequent waves of neurons split the preplate by migrating along [[radial glia]]l fibres to form the cortical plate. Each wave of migrating cells travel past their predecessors forming layers in an inside-out manner, meaning that the youngest neurons are the closest to the surface.<ref>{{cite journal |author=Nadarajah B, Parnavelas J |title=Modes of neuronal migration in the developing cerebral cortex |journal=Nat Rev Neurosci |volume=3 |issue=6 |pages=423–32 |year=2002 |pmid=12042877 |doi=10.1038/nrn845}}</ref><ref>{{cite journal |author=Rakic P |title=Mode of cell migration to the superficial layers of fetal monkey neocortex |journal=J Comp Neurol |volume=145 |issue=1 |pages=61–83 |year=1972 |pmid=4624784 |doi=10.1002/cne.901450105}}</ref> It is estimated that glial guided migration represents 90% of migrating neurons in human and about 75% in rodents.<ref name=pmid12050665>{{cite journal |author=Letinic K, Zoncu R, Rakic P |title=Origin of GABAergic neurons in the human neocortex |journal=[[Nature (journal)|Nature]] |volume=417 |issue=6889 |pages=645–9 |year=2002 |month= June|pmid=12050665 |doi=10.1038/nature00779}}</ref>

'''Tangential migration'''
Most interneurons migrate tangentially through multiple modes of migration to reach their appropriate location in the cortex. An example of tangential migration is the movement of interneurons from the [[ganglionic eminence]] to the cerebral cortex. One example of ongoing tangential migration in a mature organism, observed in some animals, is the [[rostral migratory stream]] connecting [[subventricular zone]] and [[olfactory bulb]].

'''Others modes of migration'''
There is also a method of neuronal migration called '''multipolar migration'''.<ref name=Tabata03>{{cite journal |author=Tabata H, Nakajima K |title=Multipolar migration: the third mode of radial neuronal migration in the developing cerebral cortex |journal=J Neurosci |volume=23 |issue=31 |pages=9996–10001 |date=5 November 2003|pmid=14602813 |url=http://www.jneurosci.org/cgi/content/full/23/31/9996 }}</ref><ref>{{cite journal |author=Nadarajah B, Alifragis P, Wong R, Parnavelas J |title=Neuronal migration in the developing cerebral cortex: observations based on real-time imaging |journal=Cereb Cortex |volume=13 |issue=6 |pages=607–11 |year=2003 |pmid=12764035 |doi=10.1093/cercor/13.6.607 |url=http://cercor.oxfordjournals.org/cgi/content/full/13/6/607}}</ref> This is seen in multipolar cells, which are abundantly present in the [[cortical intermediate zone]]. They do not resemble the cells migrating by locomotion or somal translocation. Instead these multipolar cells express neuronal markers and extend multiple thin processes in various directions independently of the radial glial fibers.<ref name=Tabata03/>

==Neurotrophic factors==
The survival of neurons is regulated by survival factors, called trophic factors. The neurotrophic hypothesis was formulated by Victor Hamburger and [[Rita Levi Montalcini]] based on studies of the developing nervous system. Victor Hamburger discovered that implanting an extra limb in the developing chick led to an increase in the number of spinal motor neurons. Initially he thought that the extra limb was inducing proliferation of motor neurons, but he and his colleagues later showed that there was a great deal of motor neuron death during normal development, and the extra limb prevented this cell death. According to the neurotrophic hypothesis, growing axons compete for limiting amounts of target-derived trophic factors and axons that neurons that fail to receive insufficient trophic support die by apoptosis. It is now clear that factors produced by a number of sources contribute to neuronal survival.

[[Nerve Growth Factor]] (NGF): Rita Levi Montalcini and Stanley Cohen purified the first trophic factor, Nerve Growth Factor (NGF), for which they received the Nobel Prize. There are three NGF-related trophic factors: BDNF, NT3, and NT4, which regulate survival of various neuronal populations. The Trk proteins act as receptors for NGF and related factors. Trk is a receptor tyrosine kinase. Trk dimerization and phosphorylation leads to activation of various intracellular signaling pathways including the MAP kinase, Akt, and PKC pathways.

CNTF: Ciliary neurotrophic factor is another protein that acts as a survival factor for motor neurons. CNTF acts via a receptor complex that includes CNTFRα, GP130, and LIFRβ. Activation of the receptor leads to phosphorylation and recruitment of the JAK kinase, which in turn phosphorylates LIFRβ. LIFRβ acts as a docking site for the STAT transcription factors. JAK kinase phosphorylates STAT proteins, which dissociate from the receptor and translocate to the nucleus to regulate gene expression.

GDNF: Glial derived neurotrophic factor is a member of the TGFb family of proteins, and is a potent trophic factor for striatal neurons. The functional receptor is a heterodimer, composed of type 1 and type 2 receptors. Activation of the type 1 receptor leads to phosphorylation of Smad proteins, which translocate to the nucleus to activate gene expression.

==Synapse formation==

'''Neuromuscular junction'''
Much of our understanding of synapse formation comes from studies at the neuromuscular junction. The transmitter at this synapse is acetylcholine. The acetylcholine receptor (AchR) is present at the surface of muscle cells before synapse formation. The arrival of the nerve induces clustering of the receptors at the synapse. McMahan and Sanes showed that the synaptogenic signal is concentrated at the [[basal lamina]]. They also showed that the synaptogenic signal is produced by the nerve, and they identified the factor as [[Agrin]]. Agrin induces clustering of AchRs on the muscle surface and synapse formation is disrupted in agrin knockout mice. Agrin transuces the signal via MuSK receptor to [[rapsyn]]. Fischbach and colleagues showed that receptor subunits are selectively transcribed from nuclei next to the synaptic site. This is mediated by neuregulins.

In the mature synapse each muscle fiber is innervated by one motor neuron. However, during development many of the fibers are innervated by multiple axons. Lichtman and colleagues have studied the process of synapses elimination. This is an activity-dependent event. Partial blockage of the receptor leads to retraction of corresponding presynaptic terminals.

'''CNS synapses'''
Agrin appears not to be a central mediator of CNS synapse formation and there is active interest in identifying signals that mediate CNS synaptogenesis. Neurons in culture develop synapses that are similar to those that form in vivo, suggesting that synaptogenic signals can function properly in vitro. CNS synaptogenesis studies have focused mainly on glutamatergic synapses. Imaging experiments show that dendrites are highly dynamic during development and often initiate contact with axons. This is followed by recruitment of postsynaptic proteins to the site of contact. Stephen Smith and colleagues have shown that contact initiated by dendritic filopodia can develop into synapses.

Induction of synapse formation by glial factors: Barres and colleagues made the observation that factors in glial conditioned media induce synapse formation in retinal ganglion cell cultures. Synapse formation in the CNS is correlated with astrocyte differentiation suggesting that astrocytes might provide a synaptogenic factor. The identity of the astrocytic factors is not yet known.

Neuroligins and SynCAM as synaptogenic signals: Sudhof, Serafini, Scheiffele and colleagues have shown that neuroligins and SynCAM can act as factors that will induce presynaptic differentiation. Neuroligins are concentrated at the postsynaptic site and act via neurexins concentrated in the presynaptic axons. SynCAM is a cell adhesion molecule that is present in both pre- and post-synaptic membranes.

==Synapse elimination==
Several motorneurones compete for each neuromuscular junction, but only one survives till adulthood. Competition ''in vitro'' has been shown to involve a limited neurotrophic substance that is released, or that neural activity infers advantage to strong post-synaptic connections by giving resistance to a toxin also released upon nerve stimulation. ''In vivo'' it is suggested that muscle fibres select the strongest neuron through a retrograde signal.

==See also==
{{Portal|Neuroscience}}
* [[Neural development in humans]]
* [[Axon guidance]]
* [[Pioneer neuron]]
* [[Neural Darwinism]]
* [[Neurodevelopmental disorder]]
* [[Pre- and perinatal psychology]]
* [[Brain development timelines]]
* [[Malleable intelligence]]
* [[Human brain development timeline]]
* [[Mouse brain development timeline]]
* [[Macaque brain development timeline]]

==References==
{{Reflist|2}}

==External links==
* ''[http://www.neuraldevelopment.com/ Neural Development]'' (peer-reviewed open access journal).
* ''[http://www.translatingtime.net/ Translating Neurodevelopmental Time Across Mammalian Species]''

{{Neuroscience}}
{{Development of nervous system}}

{{DEFAULTSORT:Neural Development}}
[[Category:Developmental biology]]
[[Category:Embryology of nervous system]]
[[Category:Developmental neuroscience]]

[[de:Entwicklungsneurobiologie]]
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Neuroanatomy

2011-09-02T18:16:32Z

PhineasG: general re-write, corrections, removal of irrelevant info... began drafting section on planes of orientation and terms of direction, but obviously needs more work.

{{incomplete|date=January 2010}}
[[Image:Gehirn, medial - beschriftet lat.svg|right|thumbnail|Anatomy of the human brain.]]

'''Neuroanatomy''' is the study of the physical structure and organization of the [[nervous system]]. In contrast to animals with [[radial symmetry]], whose nervous system consists of a distributed network of cells, animals with [[bilateral symmetry]] have segregated, defined nervous systems, and thus we can begin to speak of their neuroanatomy. In [[vertebrates]], both the internal structure of the [[brain]] and [[spinal cord]] (together called the [[central nervous system]], or CNS) and the routes of the nerves that connect to the rest of the body (known as the [[peripheral nervous system]], or PNS) are extremely elaborate. The delineation of distinct structures and regions of the nervous system has been critical in investigating how it works. For example, much of what neuroscientists have learned comes from observing how damage or "lesions" to specific brain areas affects [[behavior]] or other neural functions.

== History ==
The first known written record of a study of the anatomy of the human brain is the ancient Egyptian document the Edwin Smith Papyrus.<ref name = ESSP>Atta, H. M. "Edwin Smith Surgical Papyrus: The Oldest Known Surgical Treatise". American Surgeon, 1999, 65(12), 1190-1192.</ref> The next major development in neuroanatomy was some thousand years later when the Greek Alcmaeon determined that the brain and not the heart ruled the body and that the senses were dependent on the brain.<ref name = RF>Rose, F., "Cerebral Localization in Antiquity". Journal of the History of the Neurosciences, 2009, 18(3), 239-247.</ref>

After Alcmaeon’s findings, many scientists, philosophers, and physicians from around the world continued to contribute to the understanding of neuroanatomy, notably: Galen, Herophilus, Rhazes and Erasistratus. Herophilus and Erasistratus of Alexandria were perhaps the most influential Greek neuroscientists with their studies involving dissecting the brains.<ref name = RF/> For several hundred years afterward, with the cultural taboo of dissection, no major progress occurred in neuroscience. However, Pope Sixtus IV effectively revitalized the study of neuroanatomy by altering the papal policy and allowing human dissection. This resulted in a boom of research in neuroanatomy by artists and scientists of the Renaissance.<ref>Ginn, S. R., & Lorusso, L., "Brain, Mind, and Body: Interactions with Art in Renaissance Italy". Journal of the History of the Neurosciences, 2008, 17(3), 295-313.</ref>

In 1664, Thomas Willis, a physician and professor at Oxford University, coined the term neurology when he published his text Cerebri anatome which is considered the foundation of neuroanatomy.<ref>Neher, A., "Christopher Wren, Thomas Willis and the Depiction of the Brain and Nerves". Journal of Medical Humanities, 2009, 30(3), 191-200.</ref> The next four hundred some years has produced a great deal of documentation and study of the neural systems.

== Tools ==

Modern developments in neuroanatomy are directly correlated to the technologies used to perform research. Therefore it is necessary to discuss the various tools that are available.

Many of the [[histological]] techniques used to study other tissues can be applied to the nervous system as well. However, there are some techniques that have been developed especially for the study of neuroanatomy. Here are four examples:

1) The classic [[Golgi stain]] uses [[potassium dichromate]] and [[silver nitrate]] to stain neurons' [[dendrites]] and cell bodies in brown and black, allowing researchers to trace the paths of their thin processes in a slice of nervous tissue.

2) By expressing variable amounts of red, green, and blue fluorescent proteins in the brain, the so-called "[[brainbow]]" mutant mouse allows the combinatorial visualization of many different colors in neurons. This tags neurons with enough unique colors that they can often be distinguished from their neighbors with [[fluorescence microscopy]], enabling researchers to map the local connections between neurons.

3) [[Nissl staining]] uses dyes to intensely stain the [[rough endoplasmic reticulum]], which is abundant in neurons. This allows researchers to distinguish between different cell types (such as neurons and [[glia]]) in various regions of the nervous system.

4) [[Magnetic resonance imaging]] has been used extensively to investigate brain [[Diffusion tensor imaging|structure]] and [[Functional magnetic resonance imaging|function]] non-invasively in healthy human subjects.

The above is of course far from an exhaustive list, but it gives a sense of what type of tools can be used to probe the structure of the nervous system.

== Model systems ==

Aside from the [[human brain]], there are many other animals whose brains and nervous systems have received extensive study, including mice, [[zebrafish]]<ref>{{cite book |url=http://books.google.com/books?id=B5QVXvbOb1YC&pg=PA1&lpg=PA1&dq#v=onepage&q&f=false |title=Neuroanatomy of the zebrafish brain: a topological atlas |author= Wullimann, Mario F.; Rupp, Barbar;, Reichert, Heinrich|year=1996 |isbn=3764351209}}</ref>, [[Drosophila melanogaster|fruit fly]]<ref>http://web.neurobio.arizona.edu/Flybrain/html/index.html</ref>, and a species of roundworm called [[Caenorhabditis elegans|C. elegans]]. Each of these has its own advantages and disadvantages as a model system. For example, the C. elegans nervous system is extremely stereotyped from one individual worm to the next. This has allowed researchers using [[electron microscopy]] to map the paths and connections of all of the approximately 300 neurons in this species. The fruit fly is widely studied in part because its genetics is very well understood and easily manipulated. The mouse is used because, as a mammal, its brain is more similar in structure to our own (e.g., it has a six-layered [[Cerebral cortex|cortex]], yet its genes can be easily modified and its reproductive cycle is relatively fast.

== Composition ==

At the tissue level, the nervous system is composed of [[neurons]], [[glial cells]], and [[extracellular matrix]]. Both neurons and glial cells come in many types (see, for example, the nervous system section of the [[list of distinct cell types in the adult human body]]). Neurons are the information-processing cells of the nervous system: they sense our environment, communicate with each other via electrical signals and [[synapse|synapses]], and produce our thoughts and movements. Glial cells maintain homeostasis, produce [[myelin]], and provide support and protection for the brain's neurons. Some glial cells ([[astrocytes]]) can even propagate intercellular [[Astrocyte#Calcium waves|calcium waves]] over long distances in response to stimulation, and release [[gliotransmitters]] in response to changes in calcium concentration. The [[extracellular matrix]] also provides support on the molecular level for the brain's cells.

At the organ level, the nervous system is composed of brain regions, such as the [[hippocampus]] in mammals or the mushroom bodies of the [[Drosophila melanogaster|fruit fly]].<ref>http://web.neurobio.arizona.edu/Flybrain/html/atlas/structures/mushroom.html</ref> These regions are often modular and serve a particular role within the general pathways of the nervous system. For example, the hippocampus is critical for forming memories. The nervous system also contains [[nerves]], which are bundles of fibers that originate from the brain and spinal cord, and branch repeatedly to innervate every part of the body. Nerves are made primarily of the [[axons]] of neurons, along with a variety of membranes that wrap around and segregate them into [[nerve fascicles]].

The vertebrate nervous system is divided into the central and peripheral nervous systems. The [[central nervous system]] (CNS) consists of the [[human brain|brain]] and [[spinal cord]], while the [[peripheral nervous system]] (PNS) is made up of all the nerves outside of the CNS that connect it to the rest of the body. The PNS is further subdivided into the somatic and autonomic nervous systems. The [[somatic nervous system]] is made up of "afferent" neurons, which bring sensory information from the sense organs to the CNS, and "efferent" neurons, which carry motor instructions out to the muscles. The [[autonomic nervous system]] also has two subdivisions, the [[sympathetic nervous system|sympathetic]] and the [[parasympathetic nervous system|parasympathetic]], which are important for regulating the body's basic internal organ functions such as heartbeat, breathing, digestion, etc.

== Orientation in neuroanatomy ==
[[Image:Structural.gif|thumb|left|Para-sagittal [[MRI]] of the head in a patient with benign familial [[macrocephaly]].]]
In anatomy in general and neuroanatomy in particular, several sets of terms are used to denote orientation and location (see [[Anatomical terms of location]]). The pairs of terms used most commonly in neuroanatomy are:
* Dorsal and ventral: dorsal refers to the top or upper side, and ventral to the bottom or lower side.
* Rostral and caudal: rostral refers to the front (towards the nose; remember, "rostral" rhymes with "nostril"!), and caudal to the back (towards the tail).
* Medial and lateral: medial is towards the middle, and lateral is towards the side (away from the middle).

Commonly used terms for planes of orientation or planes of section in neuroanatomy are "transverse", "coronal", and "sagittal".
* A transverse plane is parallel to the ground, such that it divides the body or brain into a dorsal and a ventral portion.
* A sagittal plane divides the body or brain into left and right portions, and thus moves along the medial-lateral axis (see the image above).
* A coronal plane is parallel to the face, and thus divides the the body or brain into rostral (front) and caudal (back).

The directional terms "superior" and "inferior" and the "horizontal" plane are often used interchangeably with "dorsal", "ventral", and "transverse", and are equivalent in all animals other than humans. However, because humans walk on two legs, we have evolved a kink in our central nervous system, known as the [[cephalic flexure]], which bends the rostral part of the CNS at a 90 degree angle to the caudal part, at the level of the [[brainstem]]. Thus, confusion can arise when using these terms; for example, a coronal section of the [[forebrain]], say, just behind the eyes, is in a plane parallel to the face. But as it moves in the rostral direction, it rotates, such that a coronal section of the spinal cord is parallel to the ground.

==See also==
[[Neurology]]
[[Neuroscience]]

==References==
{{reflist}}

==External links==
{{commons category}}
*[http://www.neuroanatomy.org Neuroanatomy], an annual journal of clinical neuroanatomy
*[http://www.loni.ucla.edu/Atlases/ Mouse, Rat, Primate and Human Brain Atlases (UCLA Center for Computational Biology)]
*[http://brainmaps.org brainmaps.org: High-Resolution Neuroanatomically-Annotated Brain Atlases]
*[http://braininfo.rprc.washington.edu BrainInfo for Neuroanatomy]
*[http://www.sylvius.com High quality neuroanatomical visual glossary with several hundred entries]
*[http://www.stjudebgem.org/web/mainPage/mainPage.php Brain Gene Expression Map], mouse gene expression neuroanatomical resource from [[St. Jude Children's Research Hospital]]
*[http://brancusi.usc.edu/bkms/ Brain Architecture Management System], several atlases of brain anatomy
*[http://www.dtiatlas.org White Matter Atlas], Diffusion Tensor Imaging Atlas of the Brain's White Matter Tracts

{{Neuroscience}}

[[Category:Neuroanatomy| ]]
[[Category:Nervous system]]
[[Category:Neuroscience]]

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Central nervous system

2011-08-31T21:47:49Z

PhineasG: /* Development */

The '''central nervous system''' ('''CNS''') is the part of the [[nervous system]] that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of [[bilaterian]] animals—that is, all multicellular animals except [[sponge]]s and radially symmetric animals such as [[radiata|jellyfish]]. It contains the majority of the nervous system and consists of the [[brain]] and the [[spinal cord]]. Some classifications also include the [[retina]] and the [[cranial nerves]] in the CNS. Together with the [[peripheral nervous system]], it has a fundamental role in the control of [[behavior]]. The CNS is contained within the [[dorsal cavity]], with the [[brain]] in the [[cranial cavity]] and the spinal cord in the [[spinal cavity]]. In [[vertebrate]]s, the brain is protected by the skull, while the spinal cord is protected by the vertebrae, and both are enclosed in the [[meninges]].<ref>
{{cite book
| last = Maton | first = Anthea
| coauthors = Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright
| title = Human Biology and Health
| publisher = Prentice Hall
| year = 1993
| location = Englewood Cliffs, New Jersey, USA
| pages = 132–144
| isbn = 0-13-981176-1
}}</ref>

==Development==
[[File:Development of the neural tube.png|thumb|left|Development of the neural tube]]
{{Main|Neural development}}
During early development of the vertebrate embryo, a longitudinal [[neural groove|groove]] on the [[neural plate]] gradually deepens as ridges on either side of the groove (the [[neural folds]]) become elevated, and ultimately meet, transforming the groove into a [[neural tube|closed tube]], the [[ectoderm]]al wall of which forms the rudiment of the nervous system. This tube initially differentiates into three [[Vesicle (biology)|vesicles]] (pockets): the [[prosencephalon]] at the front, the [[mesencephalon]], and, between the mesencephalon and the spinal cord, the [[rhombencephalon]]. (By six weeks in the human embryo) the prosencephalon then divides further into the [[telencephalon]] and [[diencephalon]]; and the rhombencephalon divides into the [[metencephalon]] and [[myelencephalon]].

As the vertebrate grows, these vesicles differentiate further still. The telencephalon differentiates into, among other things, the [[striatum]], the [[hippocampus]] and the [[neocortex]], and its cavity becomes the [[lateral ventricles|first and second ventricles]]. Diencephalon elaborations include the [[subthalamus]], [[hypothalamus]], [[thalamus]] and [[epithalamus]], and its cavity forms the [[third ventricle]]. The [[tectum]], [[pretectum]], [[cerebral peduncle]] and other structures develop out of the mesencephalon, and its cavity grows into the [[mesencephalic duct]] (cerebral aqueduct). The metencephalon becomes, among other things, the [[pons]] and the [[cerebellum]], the myelencephalon forms the [[medulla oblongata]], and their cavities develop into the fourth ventricle.

[[File:4 week embryo brain.jpg|thumb|left|Brain regions of a 4 week old human embryo]]

{| align=center style="width:75%" border=1 cellpadding=1 cellspacing=0
|-
| rowspan=6| Central nervous system
| rowspan=5|[[Brain]]||rowspan=2|[[Prosencephalon]]||[[Telencephalon]]||colspan=2|
[[Rhinencephalon]],
[[Amygdala]],
[[Hippocampus]],
[[Neocortex]],
[[Basal ganglia]],
[[Lateral ventricles]]
|-
|[[Diencephalon]]||colspan=2|
[[Epithalamus]],
[[Thalamus]],
[[Hypothalamus]],
[[Subthalamus]],
[[Pituitary gland]],
[[Pineal gland]],
[[Third ventricle]]
|-
| rowspan=3|[[Brain stem]]||[[Mesencephalon]]||colspan=2|
[[Tectum]],
[[Cerebral peduncle]],
[[Pretectum]],
[[Mesencephalic duct]]
|-
| rowspan=2|[[Rhombencephalon]]||[[Metencephalon]]||
[[Pons]],
[[Cerebellum]]
|-
|[[Myelencephalon]]||[[Medulla oblongata]]
|-
| colspan=5 align="left"|[[Spinal cord]]
|}

==Evolution==
{{Main|Brain}}
{{See also|Encephalization|Archicortex}}
[[File:Central nervous system.svg|thumb|right|The central nervous system (2) is a combination of the brain (1) and the spinal cord (3).]]

[[Planarians]], members of the phylum [[Platyhelminthes]] (flatworms), have the simplest, clearly defined delineation of a nervous system into a central nervous system (CNS) and a [[peripheral nervous system]] (PNS).<ref>{{cite book
| last = Hickman, Jr.
| first = Cleveland P.
| coauthors = Larry S. Roberts, Susan L. Keen, Allan Larson, Helen L'Anson, David J. Eisenhour
| title = Integrated Princinples of Zoology: Fourteenth Edition
| publisher = McGraw-Hill Higher Education
| year = 2008
| location = New York, NY, USA
| pages = 733
| isbn = 978-0-07-297004-3}}</ref>
<ref>{{cite book
| last = Campbell
| first = Neil A.
| authorlink =
| coauthors = Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
| title = Biology: Eighth Edition
| publisher = Pearson / Benjamin Cummings
| year = 2008
| location = San Francisco, CA, USA
| pages = 1065
| isbn = 978-0-8053-6844-4}}</ref>
Their primitive brain, consisting of two fused anterior ganglia, and longitudinal nerve cords form the CNS; the laterally projecting nerves form the PNS. A molecular study found that more than 95% of the 116 genes involved in the nervous system of planarians, which includes genes related to the CNS, also exist in humans.<ref>{{cite journal|author=Katsuhiko Mineta, et al.|title=Origin and evolutionary process of the CNS elucidated by comparative genomics analysis of planarian ESTs|url=http://www.pnas.org/content/100/13/7666.full.pdf+html?sid=b2a914e7-5647-4ee2-835c-bc54c4927a98|journal=PNAS|format = pdf|volume=100|issue=13|pages=7666–7671|year=2003|doi=10.1073/pnas.1332513100|pmid=12802012|pmc=164645}}</ref> Like planarians, vertebrates have a distinct CNS and PNS, though more complex than those of planarians.

The CNS of [[chordate]]s differs from that of other animals in being placed dorsally in the body, above the gut and [[notochord]]/[[Vertebral column|spine]].<ref name=Romer>Romer, A.S. (1949): ''The Vertebrate Body.'' W.B. Saunders, Philadelphia. (2nd ed. 1955; 3rd ed. 1962; 4th ed. 1970)</ref> The basic pattern of the CNS is highly conserved throughout the different species of [[vertebrates]] and during evolution. The major trend that can be observed is towards a progressive telencephalisation: the [[telencephalon]] of reptiles is only an appendix to the large [[olfactory bulb]], while in mammals it makes up most of the volume of the CNS. In the human brain, the telencephalon covers most of the [[diencephalon]] and the [[mesencephalon]]. Indeed, the [[allometry|allometric]] study of brain size among different species shows a striking continuity from rats to whales, and allows us to complete the knowledge about the evolution of the CNS obtained through [[cranial endocast]]s.

[[Mammal]]s – which appear in the fossil record after the first fishes, amphibians, and reptiles – are the only vertebrates to possess the evolutionarily recent, outermost part of the cerebral cortex known as the [[neocortex]].<ref name=MarkFBear>{{cite book
| last = Bear
| first = Mark F.
| coauthors = Barry W. Connors, Michael A. Paradiso
| title = Neuroscience: Exploring the Brain: Third Edition
| publisher = Lippincott Williams & Wilkins
| year = 2007
| location = Philadelphia, PA, USA
| pages = 196–199
| url = http://books.google.com/?id=75NgwLzueikC&printsec=frontcover&dq=neuroscience+exploring+the+brain
| isbn = 978-0-7817-6003-4}}</ref>
The neocortex of [[monotremes]] (the duck-billed [[platypus]] and several species of [[echidna|spiny anteater]]s) and of [[marsupials]] (such as [[kangaroo]]s, [[koala]]s, [[opossum]]s, [[wombat]]s, and [[Tasmanian devil]]s) lack the convolutions – [[gyri]] and [[Sulcus|sulci]] – found in the neocortex of most [[placental mammals]] ([[eutherians]]).<ref name=KentCarr>{{cite book
| last = Kent
| first = George C.
| coauthors = Robert K. Carr
| title = Comparative Anatomy of the Vertebrates: Ninth Edition
| publisher = McGraw-Hill Higher Education
| year = 2001
| location = New York, NY, USA
| pages = 408
| isbn = 0-07-303869-5}}</ref>
Within placental mammals, the size and complexity of the neocortex increased over time. The area of the neocortex of mice is only about 1/100 that of monkeys, and that of monkeys is only about 1/10 that of humans.<ref name=MarkFBear>198</ref> In addition, rats lack convolutions in their neocortex (possibly also because rats are small mammals), whereas cats have a moderate degree of convolutions, and humans have quite extensive convolutions.<ref name=MarkFBear>199</ref> Extreme convolution of the neocortex is found in [[dolphin]]s, possibly related to their complex [[Animal echolocation|echolocation]].

==Diseases of the central nervous system==
There are many central nervous system diseases, including [[List of central nervous system infections|infections]] of the central nervous system such as [[encephalitis]] and [[poliomyelitis]], [[Neurodegeneration|neurodegenerative diseases]] such as Alzheimer's disease and [[amyotrophic lateral sclerosis]], [[Autoimmune disease|autoimmune]] and inflammatory diseases such as [[multiple sclerosis]] or [[acute disseminated encephalomyelitis]], and genetic disorders such as [[Krabbe's disease]], [[Huntington's disease]], or [[adrenoleukodystrophy]]. Lastly, cancers of the central nervous system can cause severe illness and, when [[Malignant brain tumor|malignant]], can have very high mortality rates.

==See also==
* [[Glossary of anatomical terminology, definitions and abbreviations]]
* [[Central nervous system disease]]
* [[Hendry's First Law of Lamination]]
* [[Neural development]]
* [[Neuroradiology]]

==References==
{{reflist|2}}

==External links==
{{commons|Central nervous system}}
* [http://www.sylvius.com Sylvius: 400+ structure neuroanatomical visual glossary]
* [http://primate-brain.org High-Resolution Cytoarchitectural Primate Brain Atlases]
* [http://www.marymt.edu/~psychol/brain.html Human Brains: A Learning Tool].
* [http://www.humannervoussystem.info Explaining the human nervous system].
* [http://www.backrack.co.uk/nervous_index.shtml Nervous System – Back Pain – Anatomy (info on nerve pairs)].
* [http://www.mfi.ku.dk/ppaulev/content.htm Textbook in Medical Physiology And Pathophysiology, many links]
* [http://www.northland.cc.mn.us/biology/AP2Online/Fall2002/AP2PowerPoint/AP2Brainlecture_files/v3_document.htm Brain and Cranial Nerves, Anatomy and Physiology Lecture, Northland Community College]
* [http://www.sciencedaily.com/news/mind_brain/ Latest Research on the Brain and Central Nervous System] From [http://www.sciencedaily.com/ ScienceDaily]
* The [[v:Topic:Neuroscience|Department of Neuroscience]] at [[v:|Wikiversity]]
* [http://nba.uth.tmc.edu/neuroscience/s2/ii1-1.html Overview of the Central Nervous System], ''Neuroscience Online'' (electronic neuroscience textbook)

{{Nervous system}}
{{Nervous tissue}}

{{DEFAULTSORT:Central Nervous System}}
[[Category:Central nervous system| ]]

[[ar:الجهاز العصبي المركزي]]
[[ast:Sistema nerviosu central]]
[[bn:কেন্দ্রীয় স্নায়ুতন্ত্র]]
[[be:Цэнтральная нервовая сістэма]]
[[be-x-old:Цэнтральная нэрвовая сыстэма]]
[[bs:Centralni nervni sistem]]
[[br:Reizhiad nervel kreiz]]
[[bg:Централна нервна система]]
[[ca:Sistema nerviós central]]
[[cs:Centrální nervová soustava]]
[[da:Centralnervesystemet]]
[[de:Zentralnervensystem]]
[[dv:ސެންޓްރަލް ނާރވަސް ސިސްޓަމް]]
[[el:Κεντρικό Νευρικό Σύστημα]]
[[es:Sistema nervioso central]]
[[eo:Centra nerva sistemo]]
[[eu:Nerbio-sistema zentral]]
[[fa:دستگاه عصبی مرکزی]]
[[fr:Système nerveux central]]
[[gl:Sistema nervioso central]]
[[hak:Chûng-khi Sṳ̀n-kîn Ne-thúng]]
[[ko:중추신경계통]]
[[hi:केन्द्रीय तंत्रिका तंत्र]]
[[hr:Središnji živčani sustav]]
[[io:Centrala nervaro]]
[[id:Sistem saraf pusat]]
[[is:Miðtaugakerfið]]
[[it:Sistema nervoso centrale]]
[[he:מערכת העצבים המרכזית]]
[[kk:Соматикалық жүйке жүйесі]]
[[ht:Sistèm nève santral]]
[[lv:Centrālā nervu sistēma]]
[[lt:Centrinė nervų sistema]]
[[hu:Központi idegrendszer]]
[[mk:Централен нервен систем]]
[[mn:Төв мэдрэлийн тогтолцоо]]
[[nl:Centraal zenuwstelsel]]
[[ja:中枢神経系]]
[[no:Sentralnervesystemet]]
[[nn:Sentralnervesystemet]]
[[oc:Sistèma nerviós central]]
[[pl:Ośrodkowy układ nerwowy]]
[[pt:Sistema nervoso central]]
[[ro:Sistemul nervos central]]
[[ru:Центральная нервная система]]
[[simple:Central nervous system]]
[[sk:Centrálna nervová sústava]]
[[sl:Osrednje živčevje]]
[[sr:Централни нервни систем]]
[[sh:Centralni nervni sistem]]
[[fi:Keskushermosto]]
[[sv:Centrala nervsystemet]]
[[tl:Gitnang sistemang nerbyos]]
[[ta:மைய நரம்பு மண்டலம்]]
[[te:కేంద్రీయ నాడీ వ్యవస్థ]]
[[th:ระบบประสาทกลาง]]
[[tr:Merkezî sinir sistemi]]
[[uk:Центральна нервова система]]
[[ur:مرکزی عصبی نظام]]
[[vi:Hệ thần kinh trung ương]]
[[zh:中樞神經系統]]

Central nervous system

2011-08-31T21:46:41Z

PhineasG: /* Development */ changed "main article" from neuroanatomy (which has nothing about development) to neural development

The '''central nervous system''' ('''CNS''') is the part of the [[nervous system]] that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of [[bilaterian]] animals—that is, all multicellular animals except [[sponge]]s and radially symmetric animals such as [[radiata|jellyfish]]. It contains the majority of the nervous system and consists of the [[brain]] and the [[spinal cord]]. Some classifications also include the [[retina]] and the [[cranial nerves]] in the CNS. Together with the [[peripheral nervous system]], it has a fundamental role in the control of [[behavior]]. The CNS is contained within the [[dorsal cavity]], with the [[brain]] in the [[cranial cavity]] and the spinal cord in the [[spinal cavity]]. In [[vertebrate]]s, the brain is protected by the skull, while the spinal cord is protected by the vertebrae, and both are enclosed in the [[meninges]].<ref>
{{cite book
| last = Maton | first = Anthea
| coauthors = Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright
| title = Human Biology and Health
| publisher = Prentice Hall
| year = 1993
| location = Englewood Cliffs, New Jersey, USA
| pages = 132–144
| isbn = 0-13-981176-1
}}</ref>

==Development==
[[File:Development of the neural tube.png|thumb|left|Development of the neural tube]]
{{Main|Neural Development}}
During early development of the vertebrate embryo, a longitudinal [[neural groove|groove]] on the [[neural plate]] gradually deepens as ridges on either side of the groove (the [[neural folds]]) become elevated, and ultimately meet, transforming the groove into a [[neural tube|closed tube]], the [[ectoderm]]al wall of which forms the rudiment of the nervous system. This tube initially differentiates into three [[Vesicle (biology)|vesicles]] (pockets): the [[prosencephalon]] at the front, the [[mesencephalon]], and, between the mesencephalon and the spinal cord, the [[rhombencephalon]]. (By six weeks in the human embryo) the prosencephalon then divides further into the [[telencephalon]] and [[diencephalon]]; and the rhombencephalon divides into the [[metencephalon]] and [[myelencephalon]].

As the vertebrate grows, these vesicles differentiate further still. The telencephalon differentiates into, among other things, the [[striatum]], the [[hippocampus]] and the [[neocortex]], and its cavity becomes the [[lateral ventricles|first and second ventricles]]. Diencephalon elaborations include the [[subthalamus]], [[hypothalamus]], [[thalamus]] and [[epithalamus]], and its cavity forms the [[third ventricle]]. The [[tectum]], [[pretectum]], [[cerebral peduncle]] and other structures develop out of the mesencephalon, and its cavity grows into the [[mesencephalic duct]] (cerebral aqueduct). The metencephalon becomes, among other things, the [[pons]] and the [[cerebellum]], the myelencephalon forms the [[medulla oblongata]], and their cavities develop into the fourth ventricle.

[[File:4 week embryo brain.jpg|thumb|left|Brain regions of a 4 week old human embryo]]

{| align=center style="width:75%" border=1 cellpadding=1 cellspacing=0
|-
| rowspan=6| Central nervous system
| rowspan=5|[[Brain]]||rowspan=2|[[Prosencephalon]]||[[Telencephalon]]||colspan=2|
[[Rhinencephalon]],
[[Amygdala]],
[[Hippocampus]],
[[Neocortex]],
[[Basal ganglia]],
[[Lateral ventricles]]
|-
|[[Diencephalon]]||colspan=2|
[[Epithalamus]],
[[Thalamus]],
[[Hypothalamus]],
[[Subthalamus]],
[[Pituitary gland]],
[[Pineal gland]],
[[Third ventricle]]
|-
| rowspan=3|[[Brain stem]]||[[Mesencephalon]]||colspan=2|
[[Tectum]],
[[Cerebral peduncle]],
[[Pretectum]],
[[Mesencephalic duct]]
|-
| rowspan=2|[[Rhombencephalon]]||[[Metencephalon]]||
[[Pons]],
[[Cerebellum]]
|-
|[[Myelencephalon]]||[[Medulla oblongata]]
|-
| colspan=5 align="left"|[[Spinal cord]]
|}

==Evolution==
{{Main|Brain}}
{{See also|Encephalization|Archicortex}}
[[File:Central nervous system.svg|thumb|right|The central nervous system (2) is a combination of the brain (1) and the spinal cord (3).]]

[[Planarians]], members of the phylum [[Platyhelminthes]] (flatworms), have the simplest, clearly defined delineation of a nervous system into a central nervous system (CNS) and a [[peripheral nervous system]] (PNS).<ref>{{cite book
| last = Hickman, Jr.
| first = Cleveland P.
| coauthors = Larry S. Roberts, Susan L. Keen, Allan Larson, Helen L'Anson, David J. Eisenhour
| title = Integrated Princinples of Zoology: Fourteenth Edition
| publisher = McGraw-Hill Higher Education
| year = 2008
| location = New York, NY, USA
| pages = 733
| isbn = 978-0-07-297004-3}}</ref>
<ref>{{cite book
| last = Campbell
| first = Neil A.
| authorlink =
| coauthors = Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
| title = Biology: Eighth Edition
| publisher = Pearson / Benjamin Cummings
| year = 2008
| location = San Francisco, CA, USA
| pages = 1065
| isbn = 978-0-8053-6844-4}}</ref>
Their primitive brain, consisting of two fused anterior ganglia, and longitudinal nerve cords form the CNS; the laterally projecting nerves form the PNS. A molecular study found that more than 95% of the 116 genes involved in the nervous system of planarians, which includes genes related to the CNS, also exist in humans.<ref>{{cite journal|author=Katsuhiko Mineta, et al.|title=Origin and evolutionary process of the CNS elucidated by comparative genomics analysis of planarian ESTs|url=http://www.pnas.org/content/100/13/7666.full.pdf+html?sid=b2a914e7-5647-4ee2-835c-bc54c4927a98|journal=PNAS|format = pdf|volume=100|issue=13|pages=7666–7671|year=2003|doi=10.1073/pnas.1332513100|pmid=12802012|pmc=164645}}</ref> Like planarians, vertebrates have a distinct CNS and PNS, though more complex than those of planarians.

The CNS of [[chordate]]s differs from that of other animals in being placed dorsally in the body, above the gut and [[notochord]]/[[Vertebral column|spine]].<ref name=Romer>Romer, A.S. (1949): ''The Vertebrate Body.'' W.B. Saunders, Philadelphia. (2nd ed. 1955; 3rd ed. 1962; 4th ed. 1970)</ref> The basic pattern of the CNS is highly conserved throughout the different species of [[vertebrates]] and during evolution. The major trend that can be observed is towards a progressive telencephalisation: the [[telencephalon]] of reptiles is only an appendix to the large [[olfactory bulb]], while in mammals it makes up most of the volume of the CNS. In the human brain, the telencephalon covers most of the [[diencephalon]] and the [[mesencephalon]]. Indeed, the [[allometry|allometric]] study of brain size among different species shows a striking continuity from rats to whales, and allows us to complete the knowledge about the evolution of the CNS obtained through [[cranial endocast]]s.

[[Mammal]]s – which appear in the fossil record after the first fishes, amphibians, and reptiles – are the only vertebrates to possess the evolutionarily recent, outermost part of the cerebral cortex known as the [[neocortex]].<ref name=MarkFBear>{{cite book
| last = Bear
| first = Mark F.
| coauthors = Barry W. Connors, Michael A. Paradiso
| title = Neuroscience: Exploring the Brain: Third Edition
| publisher = Lippincott Williams & Wilkins
| year = 2007
| location = Philadelphia, PA, USA
| pages = 196–199
| url = http://books.google.com/?id=75NgwLzueikC&printsec=frontcover&dq=neuroscience+exploring+the+brain
| isbn = 978-0-7817-6003-4}}</ref>
The neocortex of [[monotremes]] (the duck-billed [[platypus]] and several species of [[echidna|spiny anteater]]s) and of [[marsupials]] (such as [[kangaroo]]s, [[koala]]s, [[opossum]]s, [[wombat]]s, and [[Tasmanian devil]]s) lack the convolutions – [[gyri]] and [[Sulcus|sulci]] – found in the neocortex of most [[placental mammals]] ([[eutherians]]).<ref name=KentCarr>{{cite book
| last = Kent
| first = George C.
| coauthors = Robert K. Carr
| title = Comparative Anatomy of the Vertebrates: Ninth Edition
| publisher = McGraw-Hill Higher Education
| year = 2001
| location = New York, NY, USA
| pages = 408
| isbn = 0-07-303869-5}}</ref>
Within placental mammals, the size and complexity of the neocortex increased over time. The area of the neocortex of mice is only about 1/100 that of monkeys, and that of monkeys is only about 1/10 that of humans.<ref name=MarkFBear>198</ref> In addition, rats lack convolutions in their neocortex (possibly also because rats are small mammals), whereas cats have a moderate degree of convolutions, and humans have quite extensive convolutions.<ref name=MarkFBear>199</ref> Extreme convolution of the neocortex is found in [[dolphin]]s, possibly related to their complex [[Animal echolocation|echolocation]].

==Diseases of the central nervous system==
There are many central nervous system diseases, including [[List of central nervous system infections|infections]] of the central nervous system such as [[encephalitis]] and [[poliomyelitis]], [[Neurodegeneration|neurodegenerative diseases]] such as Alzheimer's disease and [[amyotrophic lateral sclerosis]], [[Autoimmune disease|autoimmune]] and inflammatory diseases such as [[multiple sclerosis]] or [[acute disseminated encephalomyelitis]], and genetic disorders such as [[Krabbe's disease]], [[Huntington's disease]], or [[adrenoleukodystrophy]]. Lastly, cancers of the central nervous system can cause severe illness and, when [[Malignant brain tumor|malignant]], can have very high mortality rates.

==See also==
* [[Glossary of anatomical terminology, definitions and abbreviations]]
* [[Central nervous system disease]]
* [[Hendry's First Law of Lamination]]
* [[Neural development]]
* [[Neuroradiology]]

==References==
{{reflist|2}}

==External links==
{{commons|Central nervous system}}
* [http://www.sylvius.com Sylvius: 400+ structure neuroanatomical visual glossary]
* [http://primate-brain.org High-Resolution Cytoarchitectural Primate Brain Atlases]
* [http://www.marymt.edu/~psychol/brain.html Human Brains: A Learning Tool].
* [http://www.humannervoussystem.info Explaining the human nervous system].
* [http://www.backrack.co.uk/nervous_index.shtml Nervous System – Back Pain – Anatomy (info on nerve pairs)].
* [http://www.mfi.ku.dk/ppaulev/content.htm Textbook in Medical Physiology And Pathophysiology, many links]
* [http://www.northland.cc.mn.us/biology/AP2Online/Fall2002/AP2PowerPoint/AP2Brainlecture_files/v3_document.htm Brain and Cranial Nerves, Anatomy and Physiology Lecture, Northland Community College]
* [http://www.sciencedaily.com/news/mind_brain/ Latest Research on the Brain and Central Nervous System] From [http://www.sciencedaily.com/ ScienceDaily]
* The [[v:Topic:Neuroscience|Department of Neuroscience]] at [[v:|Wikiversity]]
* [http://nba.uth.tmc.edu/neuroscience/s2/ii1-1.html Overview of the Central Nervous System], ''Neuroscience Online'' (electronic neuroscience textbook)

{{Nervous system}}
{{Nervous tissue}}

{{DEFAULTSORT:Central Nervous System}}
[[Category:Central nervous system| ]]

[[ar:الجهاز العصبي المركزي]]
[[ast:Sistema nerviosu central]]
[[bn:কেন্দ্রীয় স্নায়ুতন্ত্র]]
[[be:Цэнтральная нервовая сістэма]]
[[be-x-old:Цэнтральная нэрвовая сыстэма]]
[[bs:Centralni nervni sistem]]
[[br:Reizhiad nervel kreiz]]
[[bg:Централна нервна система]]
[[ca:Sistema nerviós central]]
[[cs:Centrální nervová soustava]]
[[da:Centralnervesystemet]]
[[de:Zentralnervensystem]]
[[dv:ސެންޓްރަލް ނާރވަސް ސިސްޓަމް]]
[[el:Κεντρικό Νευρικό Σύστημα]]
[[es:Sistema nervioso central]]
[[eo:Centra nerva sistemo]]
[[eu:Nerbio-sistema zentral]]
[[fa:دستگاه عصبی مرکزی]]
[[fr:Système nerveux central]]
[[gl:Sistema nervioso central]]
[[hak:Chûng-khi Sṳ̀n-kîn Ne-thúng]]
[[ko:중추신경계통]]
[[hi:केन्द्रीय तंत्रिका तंत्र]]
[[hr:Središnji živčani sustav]]
[[io:Centrala nervaro]]
[[id:Sistem saraf pusat]]
[[is:Miðtaugakerfið]]
[[it:Sistema nervoso centrale]]
[[he:מערכת העצבים המרכזית]]
[[kk:Соматикалық жүйке жүйесі]]
[[ht:Sistèm nève santral]]
[[lv:Centrālā nervu sistēma]]
[[lt:Centrinė nervų sistema]]
[[hu:Központi idegrendszer]]
[[mk:Централен нервен систем]]
[[mn:Төв мэдрэлийн тогтолцоо]]
[[nl:Centraal zenuwstelsel]]
[[ja:中枢神経系]]
[[no:Sentralnervesystemet]]
[[nn:Sentralnervesystemet]]
[[oc:Sistèma nerviós central]]
[[pl:Ośrodkowy układ nerwowy]]
[[pt:Sistema nervoso central]]
[[ro:Sistemul nervos central]]
[[ru:Центральная нервная система]]
[[simple:Central nervous system]]
[[sk:Centrálna nervová sústava]]
[[sl:Osrednje živčevje]]
[[sr:Централни нервни систем]]
[[sh:Centralni nervni sistem]]
[[fi:Keskushermosto]]
[[sv:Centrala nervsystemet]]
[[tl:Gitnang sistemang nerbyos]]
[[ta:மைய நரம்பு மண்டலம்]]
[[te:కేంద్రీయ నాడీ వ్యవస్థ]]
[[th:ระบบประสาทกลาง]]
[[tr:Merkezî sinir sistemi]]
[[uk:Центральна нервова система]]
[[ur:مرکزی عصبی نظام]]
[[vi:Hệ thần kinh trung ương]]
[[zh:中樞神經系統]]

Talk:Neuroanatomy

2011-08-31T21:04:45Z

PhineasG: proposing new section on orientation/planes of section

{{WikiProject Anatomy|class=Start|importance=High}}
{{WikiProject Neuroscience|class=Start|importance=High}}

==Article Assessment for [[WP:ANATOMY|WikiProject Anatomy]]==

Hello.
I am a member of [[WP:ANATOMY|WikiProject Anatomy]], a Wikipedia wide project that maintains and improves articles that fall under the scope of [[anatomy]]. Since your article has fallen under our scope, I have placed the correct templates on this talk page for verification. Upon review of this article, I'd like to make a few points, as shown:
*Assess articles with class and importance factors
*[[WP:MED]] does not cover anatomy, tag removed
I'm glad this article could fall within our scope, and I hope to see it grow large! Many thanks! [[User:Renaissancee|Renaissancee]] [[User_talk:Renaissancee|(talk)]] 21:12, 3 June 2009 (UTC)

==Intro definition==

In line with all other definitions, including Wictionary, I have changed the first sentence from "Neuroanatomy is the study of the anatomical organization of the ''brain''" to "Neuroanatomy is the study of the anatomical organization of the ''nervous system''" 
American Heritage Dictionary of the English Language: 1. The branch of anatomy that deals with the nervous system.
2. The neural structure of a body part or organ: the neuroanatomy of the eye.

Encarta® World English Dictionary, North American Edition:
1. The structure of the nervous system.
2. Branch of anatomy that studies the structure of the nervous system.

Merriam-Webster's Online Dictionary, 11th Edition:
The anatomy of nervous tissue and the nervous system.

Wictionary:
1. (anatomy) The anatomy of the nervous system.
2. (anatomy) The structure of the nerves of a specific organ or organism.

Webster's New World College Dictionary, 4th Ed.:
A branch of anatomy dealing with the nervous system.

Dorland's Illustrated Medical Dictionary:
Anatomy of the nervous system.

Probert Encyclopaedia of Medicine:
The study of the structure of the nervous system.

[[User:Anthonyhcole|Anthony]] ([[User talk:Anthonyhcole|talk]]) 05:54, 4 October 2009 (UTC)

:Yeah, good, that's a ''no-brainer''. (Sorry.) [[User:Looie496|Looie496]] ([[User talk:Looie496|talk]]) 13:34, 4 October 2009 (UTC)
|:) [[User:Anthonyhcole|Anthony]] ([[User talk:Anthonyhcole|talk]]) 06:48, 6 October 2009 (UTC)

==add orientation / planes of section?==
seeing as the article on [[Anatomical terms of location#Planes|anatomical terms of location]] is generally a mess, and particularly bad on the (admittedly confusing) issue of human neuroanatomy, i propose adding a section here for the terms of orientation and planes of section (coronal/horizontal/saggital, dorsal/anterior, etc) and, critically, editing other neuroscience-related articles to direct here instead of to the above-mentioned page. what say you all? [[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 21:04, 31 August 2011 (UTC)

Cerebral aqueduct

2011-08-31T20:03:25Z

PhineasG: /* Additional images */

{{Infobox Brain|
Name = Cerebral aqueduct |
Latin = aqueductus mesencephali (cerebri) |
GraySubject = 188 |
GrayPage = 806 |
Image = cn3nucleus.png |
Caption = Section through [[superior colliculus]] showing path of [[oculomotor nerve]]. |
Image2 = Gray736.png |
Caption2 = Drawing of a cast of the ventricular cavities, viewed from the side. |
IsPartOf = |
Components = |
Artery = |
Vein = |
Acronym = |
BrainInfoType = hier |
BrainInfoNumber = 500 |
MeshName = Cerebral+Aqueduct |
MeshNumber = A08.186.211.132.659.822.187 |
}}
The '''mesencephalic duct''', also known as the '''aqueductus mesencephali''', '''aqueduct of [[Franciscus Sylvius|Sylvius]]''' or the '''cerebral aqueduct''', contains [[cerebrospinal fluid]] (CSF), is within the [[mesencephalon]] (or midbrain) and connects the [[third ventricle]] in the [[diencephalon]] to the [[fourth ventricle]], which is between the [[pons]] and [[cerebellum]].

==Development==
The cerebral aqueduct, similarly to other parts of the ventricular system of the brain, develops from the central canal of the neural tube. Specifically, the duct originates from the portion of the neural tube that is present in the developing mesencephalon, hence the name "mesencephalic duct." <ref>
{{Cite book
| last1 = Le | first1 = Tao
| first2 = Vikas | last2 = Bhushan
| first3 = Neil | last3 = Vasan
| title = [[First Aid for the USMLE Step 1: 2010 20th Anniversary Edition]]
| location = USA
| publisher = [[The McGraw-Hill Companies, Inc.]]
| year= 2010
| pages = 126
| isbn = 978-0-07-163340-6 }}
</ref>

==Pathology==
A blockage in this duct is a cause of [[hydrocephalus]].

==See also==
*[[List of regions in the human brain]]

==References==
{{Reflist}}

==External links==
* {{UMichAtlas|n2a3p2}}

==Additional images==
<gallery>
Image:Gray710.png|Transverse section through [[mid-brain]]; number 2 indicates the cerebral aqueduct.
Image:Gray711.png|Transverse section of mid-brain at level of inferior colliculi.
Image:Gray712.png|Transverse section of mid-brain at level of superior colliculi.
Image:Periaqueductal_MRI.PNG|MRI section of mid-brain.
Image:Gray720.png|Median sagittal section of brain.
Image:Gray734.png|Scheme showing relations of the ventricles to the surface of the brain.
</gallery>

{{Mesencephalon}}

[[Category:Cerebrum]]
[[Category:Neuroanatomy]]

{{neuroanatomy-stub}}

[[bg:Акведукт на Силвиус]]
[[cs:Sylviův kanálek]]
[[de:Aquaeductus mesencephali]]
[[fr:Aqueduc de Sylvius]]
[[nl:Aquaduct van Sylvius]]
[[no:Hjernens akvedukt]]
[[pl:Wodociąg mózgu]]
[[pt:Aqueduto cerebral]]
[[th:ท่อน้ำสมอง]]

Cerebral aqueduct

2011-08-31T20:02:20Z

PhineasG: /* Additional images */

{{Infobox Brain|
Name = Cerebral aqueduct |
Latin = aqueductus mesencephali (cerebri) |
GraySubject = 188 |
GrayPage = 806 |
Image = cn3nucleus.png |
Caption = Section through [[superior colliculus]] showing path of [[oculomotor nerve]]. |
Image2 = Gray736.png |
Caption2 = Drawing of a cast of the ventricular cavities, viewed from the side. |
IsPartOf = |
Components = |
Artery = |
Vein = |
Acronym = |
BrainInfoType = hier |
BrainInfoNumber = 500 |
MeshName = Cerebral+Aqueduct |
MeshNumber = A08.186.211.132.659.822.187 |
}}
The '''mesencephalic duct''', also known as the '''aqueductus mesencephali''', '''aqueduct of [[Franciscus Sylvius|Sylvius]]''' or the '''cerebral aqueduct''', contains [[cerebrospinal fluid]] (CSF), is within the [[mesencephalon]] (or midbrain) and connects the [[third ventricle]] in the [[diencephalon]] to the [[fourth ventricle]], which is between the [[pons]] and [[cerebellum]].

==Development==
The cerebral aqueduct, similarly to other parts of the ventricular system of the brain, develops from the central canal of the neural tube. Specifically, the duct originates from the portion of the neural tube that is present in the developing mesencephalon, hence the name "mesencephalic duct." <ref>
{{Cite book
| last1 = Le | first1 = Tao
| first2 = Vikas | last2 = Bhushan
| first3 = Neil | last3 = Vasan
| title = [[First Aid for the USMLE Step 1: 2010 20th Anniversary Edition]]
| location = USA
| publisher = [[The McGraw-Hill Companies, Inc.]]
| year= 2010
| pages = 126
| isbn = 978-0-07-163340-6 }}
</ref>

==Pathology==
A blockage in this duct is a cause of [[hydrocephalus]].

==See also==
*[[List of regions in the human brain]]

==References==
{{Reflist}}

==External links==
* {{UMichAtlas|n2a3p2}}

==Additional images==
<gallery>
Image:Gray710.png|Transverse section through [[mid-brain]]; number 2 indicates the cerebral aqueduct.
Image:Gray711.png|Transverse section of mid-brain at level of inferior colliculi.
Image:Gray712.png|Transverse section of mid-brain at level of superior colliculi.
Image:Gray720.png|Median sagittal section of brain.
Image:Gray734.png|Scheme showing relations of the ventricles to the surface of the brain.
Image:Periaqueductal_MRI.PNG|MRI section of mid-brain
</gallery>

{{Mesencephalon}}

[[Category:Cerebrum]]
[[Category:Neuroanatomy]]

{{neuroanatomy-stub}}

[[bg:Акведукт на Силвиус]]
[[cs:Sylviův kanálek]]
[[de:Aquaeductus mesencephali]]
[[fr:Aqueduc de Sylvius]]
[[nl:Aquaduct van Sylvius]]
[[no:Hjernens akvedukt]]
[[pl:Wodociąg mózgu]]
[[pt:Aqueduto cerebral]]
[[th:ท่อน้ำสมอง]]

Cerebral aqueduct

2011-08-31T20:00:31Z

PhineasG: /* Additional images */

{{Infobox Brain|
Name = Cerebral aqueduct |
Latin = aqueductus mesencephali (cerebri) |
GraySubject = 188 |
GrayPage = 806 |
Image = cn3nucleus.png |
Caption = Section through [[superior colliculus]] showing path of [[oculomotor nerve]]. |
Image2 = Gray736.png |
Caption2 = Drawing of a cast of the ventricular cavities, viewed from the side. |
IsPartOf = |
Components = |
Artery = |
Vein = |
Acronym = |
BrainInfoType = hier |
BrainInfoNumber = 500 |
MeshName = Cerebral+Aqueduct |
MeshNumber = A08.186.211.132.659.822.187 |
}}
The '''mesencephalic duct''', also known as the '''aqueductus mesencephali''', '''aqueduct of [[Franciscus Sylvius|Sylvius]]''' or the '''cerebral aqueduct''', contains [[cerebrospinal fluid]] (CSF), is within the [[mesencephalon]] (or midbrain) and connects the [[third ventricle]] in the [[diencephalon]] to the [[fourth ventricle]], which is between the [[pons]] and [[cerebellum]].

==Development==
The cerebral aqueduct, similarly to other parts of the ventricular system of the brain, develops from the central canal of the neural tube. Specifically, the duct originates from the portion of the neural tube that is present in the developing mesencephalon, hence the name "mesencephalic duct." <ref>
{{Cite book
| last1 = Le | first1 = Tao
| first2 = Vikas | last2 = Bhushan
| first3 = Neil | last3 = Vasan
| title = [[First Aid for the USMLE Step 1: 2010 20th Anniversary Edition]]
| location = USA
| publisher = [[The McGraw-Hill Companies, Inc.]]
| year= 2010
| pages = 126
| isbn = 978-0-07-163340-6 }}
</ref>

==Pathology==
A blockage in this duct is a cause of [[hydrocephalus]].

==See also==
*[[List of regions in the human brain]]

==References==
{{Reflist}}

==External links==
* {{UMichAtlas|n2a3p2}}

==Additional images==
<gallery>
Image:Gray710.png|Transverse section through [[mid-brain]].
Image:Gray711.png|Transverse section of mid-brain at level of inferior colliculi.
Image:Gray712.png|Transverse section of mid-brain at level of superior colliculi.
Image:Gray720.png|Median sagittal section of brain.
Image:Gray734.png|Scheme showing relations of the ventricles to the surface of the brain.
Image:Periaqueductal_MRI.PNG|MRI section of mid-brain
</gallery>

{{Mesencephalon}}

[[Category:Cerebrum]]
[[Category:Neuroanatomy]]

{{neuroanatomy-stub}}

[[bg:Акведукт на Силвиус]]
[[cs:Sylviův kanálek]]
[[de:Aquaeductus mesencephali]]
[[fr:Aqueduc de Sylvius]]
[[nl:Aquaduct van Sylvius]]
[[no:Hjernens akvedukt]]
[[pl:Wodociąg mózgu]]
[[pt:Aqueduto cerebral]]
[[th:ท่อน้ำสมอง]]

Talk:Cerebral aqueduct

2011-08-30T20:54:21Z

PhineasG: /* Coronal or transverse plane */

{{WPMED|class=stub|importance=Low}}
{{WikiProject Neuroscience|importance=Low|class=stub}}
==Move to cerebral aqueduct==
I've moved this page from [[Mesencephalic duct]] to [[Cerebral aqueduct]]. ''Cerebral aqueduct'' is used far more often than ''mesencephalic duct'' in the texts I've come across (e.g. Barr's ''The Human Nervous System: An anatomical viewpoint'') and Google reports a usage of 10:1 in favor of ''cerebral aqueduct'' as well. --[[User:Diberri|David Iberri]] ([[User talk:Diberri|talk]]) 16:43, 8 January 2006 (UTC)

==Coronal or transverse plane==
Look at the first (left side) two images in the image gallery; they show the same view but the captions disagree re which plane, [[coronal plane]] or [[transverse plane]]. --[[User:Una Smith|Una Smith]] ([[User talk:Una Smith|talk]]) 05:39, 27 November 2007 (UTC)
:This confusion arises from the presence of the "[[cephalic flexure]]" in humans, which is the kink in the central nervous system that results in the forebrain being turned ~90 degrees relative to the rest of the CNS. This was, obviously, a necessary adjustment with the evolution of upright bipedalism, to keep our eyes pointed forward when we started walking on two legs! In the first image, "coronal" is being used with respect to the nervous system, while for the second image, "transverse" is being used with respect to the (human) body orientation, i.e., a plane parallel to the ground. Both are correct and frankly, I can't decide which to change for consistency's sake, in part because the page for [[anatomical terms of location]], and particularly the section on planes of section, is a total mess. I'll try to work on that! [[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 20:54, 30 August 2011 (UTC)

List of common misconceptions

2011-02-05T00:43:39Z

PhineasG: /* The brain */

{{Redirect|Misconception|the Law & Order episode|Misconception (Law & Order)}}

{{AfDM|page=List of common misconceptions (3rd nomination)|year=2011|month=January|day=31|substed=yes|origtag=afdx|help=off}}

{{pp-semi-indef}}

:''This [[Wikipedia:WikiProject_Lists#Incomplete_lists|incomplete list]] is not intended to be exhaustive.''



This list describes fallacious ideas and beliefs which are documented and widespread as well as the actual facts concerning those ideas, where appropriate. ''Inclusion criteria'' are as follows: a misconception's main topic must have its own article; the misconception must have reliable source(s) which assert that it is a common misconception (or synonym thereof); the misconception and its reference(s) must be present in the topic article; the misconception must be currently held, as opposed to ancient or obsolete.

==History==
{{see also|List of misquotations}}

===Ancient to early modern history===
* In [[ancient Rome]], Romans did not build rooms called vomitoria in which to purge themselves after a meal.<ref>{{cite web|title=Vomitorium|url=http://oxforddictionaries.com/definition/vomitorium|work=Oxford Dictionary|publisher=Oxford Dictionaries|accessdate=2010-12-02}}</ref> [[Vomitorium|Vomitoria]] were the entranceways through which crowds entered and exited a stadium.<ref>{{cite book|last=McKeown|first=J.C.|title=A Cabinet of Roman Curiosities: Strange Tales and Surprising Facts from the World’s Greatest Empire|year=2010|publisher=Oxford University Press|isbn=0195393759, 9780195393750|pages=153–154|url=http://books.google.com/?id=YGYwlMZ3ursC&pg=PA153&dq=vomitorium+misconception#v=onepage&q=vomitorium%20misconception&f=false}}</ref>
* There is no evidence that [[Vikings]] wore horns on their helmets.<ref>{{Cite web|title=Did Vikings Wear Horned Helmets?|first=Robert |last=Wilde|url=http://europeanhistory.about.com/od/thevikings/a/histmyths6.htm|publisher=About.com}}</ref><ref>{{Cite web|title=Did Vikings really wear horns on their helmets?|url=http://www.straightdope.com/columns/read/2189/did-vikings-really-wear-horns-on-their-helmets|publisher=StraightDope.com}}</ref>
* There is no evidence that [[Iron maiden (torture)|iron maiden]]s were invented in the [[Middle Ages]] or even used for torture, despite being shown so in some media, but instead were pieced together in the 18th century from several [[artifact (archaeology)|artifacts]] found in museums in order to create spectacular objects intended for (commercial) exhibition.<ref>{{cite book
| first = Wolfgang
| last = Schild
| year = 2000
| title = Die eiserne Jungfrau. Dichtung und Wahrheit (Schriftenreihe des Mittelalterlichen Kriminalmuseums Rothenburg o. d. Tauber Nr. 3)
| pages =
| publisher =
| location = Rothenburg ob der Tauber
| id =
| url =
}}</ref>
*[[Christopher Columbus]]'s efforts to obtain support for his voyages were not hampered by a [[Europe]]an belief in a [[flat Earth]]. [[Sailor]]s and [[navigator]]s of the time knew that the [[spherical Earth|Earth was spherical]], but (correctly) disagreed with Columbus' estimate of the distance to [[India]], which was approximately {{frac|1|6}}th of the actual distance. If the Americas did not exist, and had Columbus continued to India, he would have run out of supplies before reaching it at the rate he was traveling. Without the ability to determine [[longitude]] at sea, he could not have corrected his error.{{clarify|reason=What is his error that he is correcting?|date=January 2011}} This problem remained unsolved until the 18th century, when the [[lunar distance (navigation)|lunar distance]] method emerged in parallel with efforts by inventor [[John Harrison]] to create the first [[marine chronometer]]s. The intellectual class had known<ref name="aquinas">{{Cite web|url=http://www.newadvent.org/summa/1001.htm#1|accessdate=July 31, 2010|title=Summa Theologica Question 1|last=Aquinas|first=St Thomas}}</ref> that the Earth was spherical since the works of the Greek philosophers Plato and Aristotle.<ref name="dicks">{{Cite book|last=Dicks|first=D.R.|title=Early Greek Astronomy to Aristotle|page=68|year=1970|isbn=9780801405617|publisher=Cornell University Press.|location=Ithaca, NY}}</ref> [[Eratosthenes]] made a very good estimate of the Earth's diameter in the third century BC.<ref>{{Cite book|url=http://www.lonelyplanet.com/shop_pickandmix/previews/panama-veraguas-province-preview.pdf |title=Panama - Veraguas Province |publisher=LonelyPlanet.com |page=174 |date=|accessdate=2010-06-23}}</ref><ref>{{Cite web|last=Stengle|first=Jamie|url=http://www.philly.com/inquirer/health_science/daily/20080220_Lunar_eclipse__The_view_from_historys_perspective.html|title=Lunar eclipse: The view from history's perspective|publisher= Philadelphia Inquirer |date=February 20, 2008 |publisher=Philly.com |accessdate=2009-08-29}}</ref> (See also: [[Myth of the Flat Earth]]) [[Image:Thanksgiving-Brownscombe.jpg|thumb|left|"The First Thanksgiving at Plymouth" (1914) By Jennie A. Brownscombe]]
*Contrary to the popular image of the [[Pilgrim Fathers]], the early settlers of the [[Plymouth Colony]] in present-day [[Plymouth, Massachusetts]] did not dress in black, wear buckles, or wear black steeple hats. According to [[Plimoth Plantation]] historian James W. Baker, this image was formed in the 19th century when buckles were a kind of emblem of [[wikt:quaint|quaintness]]. This is also the reason illustrators gave [[Santa Claus]] buckles.<ref>{{Cite web|last=Shenkman|first=Rick|url=http://hnn.us/articles/406.html|title=Top 10 Myths about Thanksgiving|work=HNN.us|publisher=George Mason University|date=November 21, 2001 |accessdate=2009-08-29}}</ref><ref>{{Cite news|last=Pollak|first=Michael|url=http://www.nytimes.com/1998/11/26/technology/screen-grab-mayflower-descendant-digs-deep-into-the-lore.html|title=Screen Grab; Mayflower Descendant Digs Deep Into the Lore|publisher=The New York Times|date=November 26, 1998|accessdate=2009-08-29}}</ref><ref>{{cite web|url=http://www.pbs.org/wnet/colonialhouse/print/p-teach_lesson1_answers.html|title="Mythconceptions" Quiz Answer Key |publisher=PBS.org| year=2004| work=Colonial House}}</ref><ref>{{Cite web|url=http://www.history.com/topics/mayflower-myths|title=Mayflower Myths - Thanksgiving Holiday|publisher=History.com|date=January 4, 2008|accessdate=2009-08-29}}</ref>
* [[Marie Antoinette]] did not actually use the phrase "[[let them eat cake]]" when she heard that the French peasantry was starving due to a dearth of bread. The phrase was first published in Rousseau's Confessions when Marie was only 10 years old and most scholars believe that [[Rousseau]] coined it himself, or that it was said by [[Maria Theresa of Spain|Maria-Theresa]], the wife of [[Louis XIV]]. Even Rousseau (or Maria-Theresa) did not use the exact words but actually "Qu'ils mangent de la [[brioche]]" ("Let them eat brioche [a rich type of bread]"). Marie Antoinette was a very unpopular ruler and many people therefore attribute the phrase "let them eat cake" to her, in keeping with her reputation as being hard-hearted and disconnected from her subjects.<ref>{{Cite web|last=Keener|first=Candace|url=http://history.howstuffworks.com/european-history/top-5-marie-antoinette-scandals1.htm|title=HowStuffWorks "Let Them Eat Cake"|publisher=History.howstuffworks.com|date=|accessdate=2010-06-23}}</ref>
*[[George Washington]] did not have wooden teeth. According to a study of Washington's four known dentures by a forensic anthropologist from the [[University of Pittsburgh]] (in collaboration with the [[National Museum of Dentistry]], itself associated with the [[Smithsonian Museum]]), the dentures were made of gold, hippopotamus ivory, lead, and human and animal teeth (including horse and donkey teeth).<ref>{{Cite web|author=|url=http://www.msnbc.msn.com/id/6875436/|title=Washington's False Teeth Not Wooden |publisher=MSNBC|date=January 27, 2005|accessdate=2009-08-29}}</ref>
*It is a common misconception that the signing of the [[United States Declaration of Independence|Declaration of Independence]] occurred on July 4, 1776. The final language of the document was approved by the [[Second Continental Congress]] on that date, it was printed and distributed on July 4 and 5,<ref>{{cite web| title=Declaration of Independence - A History |url=http://www.archives.gov/exhibits/charters/declaration_history.html |publisher=U.S. National Archives and Records Administration |work=archives.gov}}</ref> but the actual signing occurred on August 2, 1776.<ref>{{cite web|url=http://www.gallup.com/poll/3742/new-poll-gauges-americans-general-knowledge-levels.aspx|date=July 6, 1999|title=New Poll Gauges Americans' General Knowledge Levels|first=Steve |last=Crabtree|quote=Fifty-five percent say it commemorates the signing of the Declaration of Independence (this is a common misconception, and close to being accurate; July 4th is actually the date in 1776 when the Continental Congress approved the Declaration, which was officially signed on August 2nd.) Another 32% give a more general answer, saying that July 4th celebrates Independence Day.|publisher=Gallup News Service|accessdate=2011-01-13}}</ref>
* The [[United States Constitution]] was written on [[parchment]], not [[hemp]] paper.<ref>{{cite web|url=http://www.usconstitution.net/constfaq_q145.html |title=Constitutional FAQ Answer #145|publisher=USConstitution.net.|work= The U.S. Constitution Online.|accessdate=2011-01-13}}</ref> It is likely that drafts of the document were written on hemp, since a large portion of paper at the time was made from the material.<ref>{{cite web |first=Jack |last=Herer |title=The Emperor Wears No Clothes -- Chapter 2: Fiber and Pulp Paper|publisher=ElectricEmperor.com |url=http://www.electricemperor.com/eecdrom/HTML/EMP/02/ECH02_03.HTM |accessdate=2011-01-15 }}</ref>

===Modern history===
[[Image:Eastlake - Napoleon on the Bellerophon.jpg|thumb|''Napoleon on the Bellerophon'', a painting by [[Charles Lock Eastlake]] depicting [[Napoleon I]], who was taller than his nickname, The Little Corporal, suggests]]
* [[Napoleon I]] (Napoleon Bonaparte) (pictured) was not particularly short,<ref>{{Cite news|url=http://www.independent.co.uk/news/uk/this-britain/theory-of-napoleon-complex-is-debunked-442338.html|title=Theory of ‘Napoleon complex’ is debunked|accessdate=2009-07-13|work=The Independent|location=London|first=Terry|last=Kirby|date=2007-03-29}}</ref> and did not have a [[Napoleon complex]]. After his death in 1821, the French emperor’s height was recorded as 5 [[Foot (length)|feet]] 2 inches in [[Foot (length)#Obsolete use in different countries|French feet]]. This corresponds to 5 feet 6.5 inches in modern [[International foot|international feet]], or 1.686 [[metres]].<ref>{{Cite web|url=http://www.napoleon.org/en/essential_napoleon/faq/index.asp#ancre54|title=www.napoleon.com Fondation Napoléon|publisher=Napoleon.org|date=|accessdate=2009-08-29}}</ref><ref>{{Cite web|title=LA TAILLE DE NAPOLÉON|url=http://www.napoleon.org/fr/salle_lecture/articles/files/Taillenapo_RIN_89_oct1963_2006.asp|language=French|accessdate=2010-07-22}}</ref> There are competing explanations for why he was nicknamed ''le Petit Caporal'' (The Little Corporal),<ref>The Harrap’s Shorter English-French French-English Dictionary on CD-ROM</ref> but few modern scholars believe it referred to his physical stature. Another explanation is that Napoleon was often seen with his [[Imperial Guard (Napoleon I)|Imperial Guard]], which contributed to the perception of him being short because the Imperial Guards were above average height.{{citation needed|date=December 2010}}
*[[Abraham Lincoln]]'s [[Emancipation Proclamation]] of January 1863 did not immediately free all [[Slavery in the United States|American slaves]].<ref>{{Cite news|last=Cruz|first=Gilbert|url=http://www.time.com/time/nation/article/0,8599,1815936,00.html|title=A Brief History of Juneteenth|publisher=TIME|date=2008-06-18|accessdate=2009-08-29}}</ref> The Proclamation pertained only to areas within rebelling states that were not under Union control. Since those states did not recognize the power of the federal government, most slaves were not immediately freed as a direct result of the Proclamation. Regions in the South that were under [[Confederate Army|Confederate]] control when the Proclamation was issued ignored its dictum, so slave ownership persisted until Union troops captured further Southern territory. Immediately affected regions were [[Tennessee]], southern [[Louisiana]], and parts of [[Virginia]].<ref>{{Cite web|url=http://www.history.umd.edu/Freedmen/chronol.htm|title=Chronology of the Civil War|publisher=History.umd.edu|date=2008-10-13|accessdate=2009-08-29}}</ref> It was only with the adoption of the [[Thirteenth Amendment to the United States Constitution|Thirteenth Amendment]] in 1865 that slavery was officially abolished in all of the United States. Thirty-six of the United States recognize June 19 as a holiday, [[Juneteenth]], celebrating the anniversary of the day the abolition of slavery was announced in Texas in 1865.
* Italian dictator [[Benito Mussolini]] did not “make the trains run on time”. Much of the repair work had been performed before Mussolini and the [[National Fascist Party|Fascists]] came to power in 1922. Accounts from the era also suggest that the Italian railways’ legendary adherence to timetables was more myth than reality.<ref>{{Cite news|url=http://www.independent.co.uk/opinion/rear-window-making-italy-work-did-mussolini-really-get-the-trains-running-on-time-1367688.html|title=Rear Window: Making Italy work: Did Mussolini really get the trains running on time|accessdate=2010-09-2013|work=The Independent|location=London|first=BRIAN|last=CATHCART|date=1994-04-03}}</ref> Mussolini's trains were subject to frequent labour disruptions due to his conflict with labour unions.
* During the German [[Invasion of Poland]] in 1939, there is no evidence of [[Polish Cavalry]] mounting a brave but futile charge against German [[tank]]s using lances and sabres. This seems to have its origins in German propaganda efforts following the [[Charge at Krojanty]] in which a Polish cavalry brigade surprised German infantry in the open and charged with sabres until driven off by [[armoured car (military)|armoured cars]]. While Polish cavalry still carried the sabre for such opportunities, they were trained to fight as highly mobile, dismounted infantry and issued with light anti-tank weapons.<ref>''If a single image dominates the popular perception of the Polish campaign of 1939, it is the scene of Polish cavalry bravely charging the Panzers with their lances. Like many other details of the campaign, it is a myth that was created by German wartime propaganda and perpetuated by sloppy scholarship. Yet such myths have also been embraced by the Poles themselves as symbols of their wartime gallantry, achieving a cultural resonance in spite of their variance with the historical record.'' - Steven J. ZALOGA: ''Poland 1939 - The birth of Blitzkrieg''. Oxford: [[Osprey Publishing]], 2002. [http://www.panzerworld.net/fallweiss.html#polishcavalry Panzerworld.net]</ref>
* During [[World War II]], King [[Christian X of Denmark]] did not thwart [[Nazi]] attempts to identify [[Jew]]s by wearing a yellow star himself. Jews in Denmark were never forced to wear the Star of David. The Danes did [[Rescue of the Danish Jews|help most Jews flee the country]] before the end of the war.<ref>{{Cite web|title=The King and the Star — Myths created during the Occupation of Denmark
|url=http://www.diis.dk/graphics/CVer/Personlige_CVer/Holocaust_and_Genocide/Publikationer/holocaust_DK_kap_5.pdf|author=Vilhjálmur Örn Vilhjálmsson|publisher=Danish institute for international studies}}</ref><ref>{{Cite web|title=Some Essential Definitions & Myths Associated with the Holocaust|url=http://www.chgs.umn.edu/histories/myths.html|publisher=Center for Holocaust and Genocide Studies - University of Minnesota }}</ref>
* [[John F. Kennedy]]'s words "{{lang|de|[[Ich bin ein Berliner]]}}" are standard German for "I am a Berliner".<ref>{{Cite book|last=Daum|first=Andreas W.|title=Kennedy in Berlin|publisher=Cambridge University Press|pages=148–149|year=2007|url=http://books.google.com/?id=IrK1TG34vw8C&lpg=PP1&pg=PT156#v=onepage&q=|isbn=3506719912}}</ref><ref>{{Cite web|url=http://www.canoo.net/services/OnlineGrammar/Wort/Artikel/Gebrauch/ArtIndef.html|title=Gebrauch des unbestimmten Artikels (German, "Use of the indefinite article")|author=Canoo Engineering AG|accessdate=2010-07-05}}</ref> An [[urban legend]] has it that due to his use of the indefinite article ''{{lang|de|ein}}'', ''{{lang|de|Berliner}}'' is translated as ''jam doughnut'', and that the population of Berlin was amused by the supposed mistake. The word ''{{lang|de|Berliner}}'' is not commonly used in Berlin to refer to the ''{{lang|de|[[Berliner (pastry)|Berliner Pfannkuchen]]}}''; they are simply called ''{{lang|de|Pfannkuchen}}''.<ref>[[:de:Ich bin ein Berliner|German wikipedia article on the speech in question]]</ref> In other parts of Germany, though, the term "Berliner" actually also is used for the product in question, so there is a grain of truth in the myth, but of course no Berliner assumed a mistake in the quote.
* According to various polls, between 20 to 24% of [[USA|Americans]] incorrectly [[Barack Obama religion conspiracy theories|believe]] that [[Barack Obama]] is a [[Muslim]].<ref>{{cite web|url=http://www.washingtonpost.com/wp-dyn/content/article/2010/08/18/AR2010081806913.html?hpid=topnews|title=Poll shows more Americans think Obama is a Muslim|publisher=washingtonpost.com|date=2010-08-19|accessdate=2011-01-07}}</ref> The [[White House]] describes Obama as a "devout [[Christian]]" who prays every day.<ref>{{cite web|url=http://www.nydailynews.com/news/politics/2010/08/19/2010-08-19_one_in_five_americans_believe_president_barack_obama_is_a_muslim_poll.html|title=24% of Americans mistakenly believe President Obama is a Muslim: poll|publisher=NYDailyNews.com|date=2010-08-19|accessdate=2011-01-07}}</ref>

==Legislation and crime==
*[[Entrapment]] law in the [[United States]] does not require police officers to identify themselves as police in the case of a sting or other undercover work.<ref>{{Cite web|url=http://www.snopes.com/risque/hookers/cop.asp|title=Snopes on Entrapment|publisher=Snopes.com|date=|accessdate=2009-08-29}}</ref> The law is specifically concerned with enticing people to commit crimes they would not have considered in the normal course of events.<ref>''Sloane'' (1990) 49 A Crim R 270. See also [[agent provocateur]]</ref>
*It is frequently rumored that the expression "[[rule of thumb]]", which is used to indicate a technique for generating a quick estimate, was originally coined from a law allowing a man to beat his wife with a stick, provided it was not thicker than the width of his thumb.<ref>{{cite web|url=http://www.lincolnminutemen.org/history/articles/hafner_rule_of_thumb.html|title=Another Myth in Splinters: “Rule of Thumb”|accessdate=January 6, 2011}}</ref> In fact, the origin of this phrase remains uncertain, but the false etymology has been broadly printed in papers and media such as ''[[The Washington Post]]'' (1989), [[CNN]] (1993), and ''[[Time Magazine]]'' (1983).<ref>{{cite book|title=Who stole feminism?: how women have betrayed women|publisher=Simon and Schuster|year=1995|author=Christina Hoff Sommers|isbn=0684801566|url=http://books.google.com/?id=EIUtJziqIqAC&printsec=frontcover&dq=Who+Stole+Feminism%3F+How+Women+Have+Betrayed+Women#v=onepage&q&f=false}}</ref>
*It is often asserted that [[Knife fight|knife attacks]] are more dangerous than an attack with a [[firearm]] ("knives are more lethal than guns").<ref>E.g., [http://www.timesonline.co.uk/tol/news/uk/crime/article3950331.ece The Times, 17 May 2008]</ref> While [[self-defense]] instructors often make a point of emphasizing that a knife attack may very easily result in death,<ref>E.g., [http://www.bladecombat.com/knifemyths.html bladecombat.com], [http://www.alljujitsu.com/self-defense-programs.html alljujitsu.com]</ref> there is no statistical evidence that knife attacks are more likely to result in death than an attack with a handgun. A 1968 study claimed that gun attacks are five times more lethal than knife attacks. This figure has since become a controversial point of dispute in [[gun politics]]. A review of several studies published in 1983 concluded that lethality of wounds from handguns is between 1.3 and 3 times higher than lethality of wounds from knives.<ref>Lethality Effects of Guns, in ''Guns in American Society'', ed. Gregg Lee Carter , 2002, ISBN 9781576072684, p. 356-358. The 1968 study cited is F. E. Zimring, 'Is Gun Control Likely to Reduce Violent Killings?', ''University of Chicago Law Review'' 35 (1968), 721-737. Zimring's study classes as "knives" any edged or pointed weapon, resulting in a reduced death rate compared to attacks with long knives. The 1983 study cited is J. D. Wright, P. H. Rossi and K. Daly, ''Under the Gun: Weapons, Crime and Violence in America'', New York (1983), pp. 199-209.</ref>

==Food and cooking==
[[Image:Western Sushi.jpg|thumb|right|180px|Roll-style Western sushi. Contrary to a popular myth, sushi can contain any number of raw ingredients, including vegetables and other non-meat products.]]
*[[Searing]] meat does not "seal in" moisture, and in fact may actually cause meat to lose moisture. Generally, the value in searing meat is that it creates a brown crust with a rich flavor via the [[Maillard reaction]].<ref>{{Cite web|url=http://www.cookthink.com/reference/7/Does_searing_meat_really_seal_in_moisture|title=Does searing meat really seal in moisture?|publisher=Cookthink.com|date=|accessdate=2009-08-29}}</ref><ref name=McGee>{{Cite book|author=McGee, Harold|title=On Food and Cooking (Revised Edition)|publisher=Scribner|year=2004|isbn=0-684-80001-2}} Page 161, "The Searing Question".</ref>
*[[Mussel]]s that do not open when cooked may still be fully cooked and safe to eat.<ref>{{Cite web|last=Kruszelnicki|first=Karl S.|url=http://www.abc.net.au/science/articles/2008/10/29/2404364.htm|title=Mussel myth an open and shut case|publisher=Abc.net.au|date=2008-10-29|accessdate=2009-08-29}}</ref>
*Some cooks believe that food items cooked with wine or liquor will be non-alcoholic, because [[ethanol|alcohol's]] low boiling point causes it to evaporate quickly when heated. However, a study found that some of the alcohol remains: 25% after 1 hour of baking or simmering, and 10% after 2 hours.<ref>{{Cite web|url=http://www.ochef.com/165.htm|title=Does alcohol burn off in cooking?|publisher=Ochef.com|date=|accessdate=2009-08-29}}</ref>
*''[[Sushi]]'' does not mean "raw fish", and not all sushi includes raw fish.<ref>[http://books.google.com/books?id=xlZ_uopejK8C ''The complete idiot's guide to Asian cooking''] by Annie Wong, Jeffrey Yarbrough; Alpha Books, 2002; ISBN 0-02-864384-4, 9780028643847.</ref><ref>[http://books.google.com/books?id=q6tl1FmWDdQC How to Do Everything: Everything You Should Know How to Do] Rosemarie Jarski; Published by Globe Pequot, 2007; ISBN 1-59921-221-8, 9781599212210.</ref> The name sushi refers to the vinegared rice used in it. Sushi is made with ''sumeshi'', rice which has been gently folded with rice vinegar, salt, and sugar dressing.<ref>{{cite web|url=http://recipes.howstuffworks.com/sushi.htm|title=How Sushi Works|publisher=[[HowStuffWorks]]|accessdate=February 4, 2011}}</ref> The rice is traditionally topped by raw fish, cooked seafood, fish [[roe]], [[tamagoyaki|egg]], and/or vegetables such as [[cucumber]], [[daikon]] radish, and [[avocado]]. The related Japanese term, ''[[sashimi]]'', is closer in definition to "raw fish", but still not quite accurate: Sashimi can also refer to any uncooked meat or vegetable, and usually refers more to the dish's presentation than to its ingredients. The dish consisted of sushi rice and other fillings wrapped in [[nori|seaweed]] is called [[makizushi]], and includes both "long rolls" and "hand rolls".
*[[Microwave oven]]s do not cook food from the inside out. Microwave radiation penetrates food and causes direct heating only a short distance from the surface. This distance is called the [[skin depth]]. As an example, lean muscle tissue (meat) has a skin depth of only about {{convert|1|cm}} at microwave oven frequencies.<ref name=VanderVorst>{{Cite book|author=Vander Vorst, Andre|title=RF/Microwave Interaction with Biological Tissues|publisher=John Wiley and Sons|year=2006|isbn=978-0471732778}} Page 43, "Figure 1.8.</ref>
*Placing metal inside a [[microwave oven]] does not damage the oven's electronics. There are, however, other safety-related issues: [[Electric arc|Electrical arcing]] may occur on pieces of metal not designed for use in a microwave oven, and metal objects may become hot enough to damage food, skin, or the interior of the microwave oven. Metallic objects that are designed for microwave use can be used in a microwave with no danger; examples include the metalized surfaces used in [[browning sleeve]]s and pizza-cooking platforms.<ref>{{Cite web|url=http://www.patentstorm.us/patents/7112771/description.html|title=US Patent 7112771 - Microwavable metallic container}}</ref>
*Swallowed chewing gum does not take seven years to digest. In fact, chewing gum is mostly indigestible, but passes through the digestive system at the same rate as other matter.<ref>{{Cite web|url=http://www.scientificamerican.com/article.cfm?id=fact-or-fiction-chewing-gum-takes-seven-years-to-digest|title=Fact or Fiction?: Chewing Gum Takes Seven Years to Digest|publisher=[[Scientific American]]|first=John|last=Matson|date=October 11, 2007|accessdate=February 4, 2011}}</ref>

==Science==
===Astronomy===
[[Image:Great Wall of China, Satellite image.jpeg|thumb|left|300px|A satellite image of a section of the [[Great Wall of China]], running diagonally from lower left to upper right (not to be confused with the much more prominent river running from upper left to lower right). The region pictured is 12 × 12 km (7.5 × 7.5 miles).]]
*The discovery of the [[spherical Earth|spherical shape of the Earth]] does not date to the modern era or to the Middle Ages. It was well known throughout the [[Hellenistic period]]. See ''[[Myth of the Flat Earth]]''.
*It is commonly claimed that the [[Great Wall of China]] is the only man-made object visible from the Moon.{{Citation needed|date=January 2011}} This is false. None of the [[Project Apollo|Apollo]] astronauts reported seeing ''any'' specific man-made object from the Moon, and even earth-orbiting astronauts can barely see it, but city lights are easily visible on the night side of Earth from orbit.<ref>{{cite web|url=http://science.nasa.gov/science-news/science-at-nasa/2003/24mar_noseprints/ |title=Space Station Astrophotography |publisher=[[NASA]]|date=March 24, 2003|accessdate=2011-01-13}}</ref> The misconception is believed to have been popularized by [[Richard Halliburton]] decades before the first moon landing. Shuttle astronaut Jay Apt has been quoted as saying "…the Great Wall is almost invisible from only 180 miles up."<ref>{{cite web|url=http://www.snopes.com/science/greatwall.asp |title=Great Walls of Liar]|publisher=Snopes.com|accessdate=2011-01-13}}</ref>
*[[Black hole]]s, unlike their common image, do not act as "cosmic vacuum cleaners" any more than other stars.<ref>{{Cite book|last=Wolfson|first=Richard|title=Simply Einstein: relativity demystified|publisher=W. W. Norton & Company|year=2002|page=261|url=http://books.google.com/?id=OUJWKdlFKeQC&pg=PA219&lpg=PA219&dq=%22black+hole%22+%22misconception%22+%22cosmic+vacuum+cleaner%22+-wikipedia|isbn=0393051544}}</ref> The collapse of a star into a black hole is an explosive process, which means, according to [[Mass–energy equivalence]], that the resulting black hole would be of lower mass than its parent object, and actually have a weaker gravitational pull.<ref>{{Cite book|last=Misner|first=Charles W|coauthors=Kip S. Thorne, John Archibald Wheeler|title=[[Gravitation (book)|Gravitation]]|year=1973|isbn=978-0716703440|publisher=W. H. Freeman|location=New York}}{{Page needed|date=September 2010}}</ref> The source of the confusion comes from the fact that a black hole exists in a space much smaller but orders of magnitude more dense than a star, causing its gravitational pull to be much stronger closer to its surface. But, as an example, were the Sun to be replaced by a black hole of the same mass, the orbits of all the planets surrounding it would be unaffected.
*When a [[meteorite#meteor|meteor]] lands on Earth (after which it is termed a [[meteorite]]), it is not necessarily hot. A meteoroid's great speed during [[atmospheric reentry|entry]] is enough to melt or [[Sublimation (phase transition)|vaporize]] its outermost layer, but any molten material would probably be quickly blown off ([[ablation|ablated]]). The interior of the meteoroid probably does not have time to heat up because the hot rocks are poor [[conduction (heat)|conductors of heat]]. Also, atmospheric drag can slow small meteoroids to [[terminal velocity]] by the time they hit the ground, giving the surface time to cool down.<ref>{{Cite web|url=http://www.amsmeteors.org/fireballs/faqf/#9|title=American Meteor Society FAQ|publisher=AMSMeteorS.org|accessdate=2010-01-08}}</ref><ref>{{Cite book|author=Plait, Philip|authorlink=Philip Plait|year=2002|title=Bad Astronomy: Misconceptions and Misuses Revealed, from Astrology to the Moon Landing "Hoax"|publisher=John Wiley & Sons|isbn=0-471-40976-6}}</ref>{{Page needed|date=September 2010}}
*It is a common misconception that [[season]]s are caused by the [[Earth]] being closer to the [[Sun]] in the summer than in the winter. In fact, the Earth is actually farther from the Sun when it is summer in the [[Northern Hemisphere]]. Seasons are the result of the Earth being [[Axial tilt|tilted on its axis]] by 23.5 degrees. As the [[Earth's orbit|Earth orbits the Sun]], different parts of the world receive different amounts of direct sunlight. When an area of the Earth's surface is oriented perpendicular to the incoming sunlight, it will receive more radiation than it will when it is oriented at an angle to the incoming sunlight. In July, the Northern Hemisphere is tilted towards the Sun giving longer days and more direct sunlight; in January, it is tilted away. The seasons are reversed in the [[Southern Hemisphere]], which is tilted towards the Sun in January and away from the Sun in July. In [[tropics|tropical areas]] of the world, there is no noticeable change in the amount of sunlight.<ref>{{Cite web|url=http://www.adlerplanetarium.org/education/resources/sunearth/section06i.shtml|publisher=Adler Planetarium |archiveurl=http://web.archive.org/web/20071216004548/http://www.adlerplanetarium.org/education/resources/sunearth/section06i.shtml|archivedate=2007-12-16|title=Sun-Earth Connection|accessdate=2009-05-08}}</ref><ref>{{Cite web|url=http://istp.gsfc.nasa.gov/istp/outreach/sunearthmiscons.html|title=Ten Things You Thought You Knew about Sun-Earth Science|publisher=[[NASA]]|accessdate=2009-05-08}}</ref> {{see|Effect of sun angle on climate}}
*It is not easier to balance an egg on its end on the [[equinox|first day of spring]].<ref>{{Cite web|url=http://www.snopes.com/science/equinox.asp|title=Egg Balancing on Equinox|publisher=Snopes.com|date=|accessdate=2009-08-29}}</ref> In fact, the ease or difficulty of balancing an egg is the same 365 days a year. This myth is said to originate with the ''[[egg of Li Chun]]'', an ancient Chinese folk belief that it is easier to balance an egg on ''Li Chun'', the first day of spring in the [[Chinese calendar]]. In Chinese ''Li'' means setup/erect, ''Chun'' spring/egg. ''Setup spring'' is a Chinese [[solar term]], literally interpreted as erecting an egg for fun. It was introduced to the western world in a ''[[Life (magazine)|Life]]'' article in 1945, and popularized once again by self-titled "urban shaman" [[Donna Henes]], who has hosted an annual egg-balancing ceremony in New York City since the mid-1970s.<ref>{{Cite web|last=Carlson|first=Jen|url=http://gothamist.com/2007/10/31/donna_henes_urb.php|title=Donna Henes, Urban Shaman - Gothamist: New York City News, Food, Arts & Events|publisher=Gothamist|date=October 31, 2007|accessdate=2009-08-29}}</ref><ref>{{Cite web|url=http://www.knoxnews.com/news/2008/mar/20/you-can-balance-an-egg-on-its-end-today-and-any/|title=You can balance an egg on its end today … and any other day|publisher=[[Knoxville News Sentinel]]|work=Knoxnews.com|date=March 20, 2008|accessdate=2009-08-29}}</ref><ref>{{Cite web|url=http://urbanlegends.about.com/od/errata/a/equinox_eggs.htm|title=Can You Balance Eggs on End During the Spring Equinox|publisher=Urbanlegends.about.com|date=March 25, 2009| accessdate=2009-08-29}}</ref>

===Biology===
[[File:AD2009Aug08 Bombus pratorum.jpg|thumb|right|''[[Bombus pratorum]]'' over an ''[[Echinacea purpurea]]'' inflorescence; a widespread myth holds that bumblebees should be incapable of flight.]]
*The claim<ref>[[Mythbusters]] Does a Duck's Quack Echo? (Season 1, Episode 8)</ref> that a [[duck]]'s quack does not [[echo (phenomenon)|echo]] is false, although the echo may be difficult to hear for humans under some circumstances.<ref>{{Cite web|url=http://www.acoustics.salford.ac.uk/acoustics_info/duck/|title=A Duck's Quack Doesn't Echo, and no-one knows the reason why?|publisher=University of Salford Acoustics |work=Acoustics.salford.ac.uk |date=|accessdate=2010-01-13}}</ref>
*[[DNA]] is not made of [[protein]].<ref>{{Cite book|last=Regis|first=Ed|title=What Is Life?: Investigating the Nature of Life in the Age of Synthetic Biology|page=44|year=2009|isbn=978-0195383416|publisher=Oxford University Press|location=USA}}</ref><ref>{{cite journal |last1=Lakin |first1=Liz |title=The golden age of protein: an initial teacher training perspective on the biological role of proteins in our everyday lives |journal=International Journal of Consumer Studies |volume=28 |pages=127–34 |year=2004 |doi=10.1111/j.1470-6431.2003.00359.x}}</ref> DNA is instead a [[nucleic acid]]. DNA and protein are closely interrelated, however. DNA is always accompanied by proteins in the [[chromatin]] of plants and animals.<ref>{{cite web|url=http://chromatin.net/|title=Chromatin Network Home Page.|accessdate=2011-01-07}}</ref> See [[protein biosynthesis]] for DNA's involvement in assembling protein. See [[DNA replication]] for [[Enzyme|enzymatic]] proteins' involvement in assembling DNA.
*The notion that [[goldfish]] have a memory of only three seconds is false.<ref>{{Cite web|last=Hipsley|first=Anna|url=http://www.abc.net.au/news/stories/2008/02/19/2166204.htm|title=Goldfish three-second memory myth busted - ABC News (Australian Broadcasting Corporation)|publisher=Abc.net.au|date=2008-02-19|accessdate=2009-08-29}}</ref><ref>Mythbusters Goldfish Memory (Season 1, Episode 14)</ref><ref>{{Cite web|url=http://nootropics.com/intelligence/smartfish.html|title=''Goldfish Pass Memory Test''|publisher=nootropics.com|date=2003-10-01|accessdate=2009-08-29}}</ref>
*[[Lemming]]s do not engage in mass suicidal dives off cliffs when migrating. They will, however, occasionally, and unintentionally fall off cliffs when venturing into unknown territory, with no knowledge of the boundaries of the environment. The misconception is due largely to the [[Disney]] film ''[[White Wilderness (film)|White Wilderness]]'', which shot many of the migration scenes (also staged by using multiple shots of different groups of lemmings) on a large, snow-covered turntable in a studio. Photographers later pushed the lemmings off a cliff.<ref>{{Cite web|url=http://www.snopes.com/disney/films/lemmings.asp|title=Lemmings|publisher=Snopes|date=|accessdate=2009-08-29}}</ref> The misconception itself is much older, dating back to at least the late nineteenth century.<ref>{{cite journal|last=Scott|first=W.|journal=The Monthly chronicle of North-country lore and legend|year=1891|title=The Monthly chronicle of North-country lore and legend: v.1-5; Mar. 1887-Dec. 1891|month=November|volume=5|pages=523|url=http://books.google.com/books?id=W8rUAAAAMAAJ&pg=PA523#v=onepage&q&f=false|accessdate=7 January 2011}}</ref>
*[[Bat]]s are not blind. While most bat species do use [[animal echolocation|echolocation]] to augment their vision, all bat species have eyes and are capable of sight.<ref>{{Cite web|url=http://www.fws.gov/endangered/bats/miscon.htm|archiveurl=http://web.archive.org/web/20080519095139/http://www.fws.gov/endangered/bats/miscon.htm|archivedate=2008-05-19|title=Common Misconceptions About Bats|accessdate=2009-04-07}}</ref><ref>{{Cite web|url=http://www.nwf.org/News-and-Magazines/National-Wildlife/Animals/Archives/2003/American-Heritage-Animal-Cliches.aspx|title=The Truth About Animal Clichés|accessdate=2009-04-07}}</ref><ref>{{Cite web|url=http://www.collegenews.org/x2682.xml|archiveurl=http://web.archive.org/web/20080607080055/http://www.collegenews.org/x2682.xml|archivedate=2008-06-07|title=Blind as a Bat?|accessdate=2009-04-07}}</ref>
*It is a common myth that an [[earthworm]] becomes two worms when cut in half. However, only a limited number of earthworm species<ref>{{Cite web|url=http://onlinelibrary.wiley.com/doi/10.1002/jez.1401170102/abstract|title=Simultaneous anterior and posterior regeneration and other growth phenomena in Maldanid polychaetes|year=1942}}</ref> are capable of anterior [[Earthworm#Regeneration|regeneration]]. When most earthworms are bisected, only the front half of the worm (where the mouth is located) can survive, while the other half dies.<ref>{{Cite web|url=http://www.bbc.co.uk/gardening/gardening_with_children/didyouknow_worms.shtml|title=Gardening with children - Worms|publisher=BBC|date=|accessdate=2009-08-29}}</ref> Also, species of the [[planaria]] family of [[flatworm]]s actually ''do'' become two new planaria when bisected or split down the middle.<ref>{{cite journal |last1=Reddien |first1=Peter W. |last2=Alvarado |first2=Alejandro Sanchez |title=FUNDAMENTALS OF PLANARIAN REGENERATION |journal=Annual Review of Cell and Developmental Biology |volume=20 |pages=725–57 |year=2004 |pmid=15473858 |doi=10.1146/annurev.cellbio.20.010403.095114}}</ref>
*According to urban myth, the daddy longlegs spider (''[[Pholcus phalangioides]]'') is the most venomous spider in the world, but the shape of their mandibles leaves them unable to bite humans, rendering them harmless to our species. In reality, they can indeed pierce human skin, though the tiny amount of venom they carry causes only a mild burning sensation for a few seconds.<ref>Mythbusters Daddy-longlegs (Season 1, Episode 16)</ref> In addition, there is also confusion regarding the use of the name ''daddy longlegs'', because harvestmen (order ''[[Opiliones]]'', which are not spiders) and [[crane fly|crane flies]] (which are insects) are also known as ''daddy longlegs'', and share (also incorrectly) the myth of being venomous.<ref>{{Cite web|title=UCR Entomology Spiders - Daddy Long Legs|url=http://spiders.ucr.edu/daddylonglegs.html}}</ref><ref>{{Cite web|title=Spider Myths - If it could only bite|url=http://www.washington.edu/burkemuseum/spidermyth/myths/daddyvenom.html}}</ref>
*[[Euphorbia pulcherrima#Rumoured toxicity|Poinsettias]] are not highly [[Toxicity|toxic]]. While it is true that they are mildly irritating to the skin or stomach<ref name = southern>{{cite encyclopedia | title = Euphorbia | encyclopedia = The Southern Living Garden Book | editor-last = Bender | editor-first = Steve | year = 2004 | month = January | edition = 2nd | ISBN = 0-376-03910-8 | publisher = Oxmoor House | location = Birmingham, Alabama | page = 306}}</ref> and may sometimes cause [[diarrhea]] and [[vomiting]] if eaten,<ref name = fiction>{{cite web| url=http://www.medicinenet.com/script/main/art.asp?articlekey=55606| title= Are Poinsettia Plants Poisonous? Fact or Fiction?|accessdate=2007-12-21 }}</ref> an [[American Journal of Emergency Medicine]] study of 22,793 cases reported to the American Association of Poison Control Centers showed no fatalities, and furthermore that a strong majority of poinsettia exposures are accidental, involve children, and usually do not result in any type of medical treatment.<ref name = ajem>{{cite journal |author=Krenzelok EP, Jacobsen TD, Aronis JM |title=Poinsettia exposures have good outcomes…just as we thought |journal=[[American Journal of Emergency Medicine|Am J Emerg Med]] |volume=14 |issue=7 |pages=671–4 |year=1996 |month=November |pmid=8906768 |doi=10.1016/S0735-6757(96)90086-8 |url=}}</ref>
*[[Ostrich]]es do not bury their heads in the sand. This tale originates from the fact that the male ostrich will dig a large hole (up to 6 to 8 feet wide and 2 to 3 feet deep) in the sand for the eggs. Predators cannot see the eggs across the countryside which gives the nest some measure of protection. The female and male take turns sitting on the eggs and, because of the indention in the ground, usually just blend into the horizon. All birds turn their eggs (with their beaks) several times a day during the incubation period. From a distance it may appear as though the bird has its head in the sand.<ref>{{Cite web|title=Facts about ostriches|url=http://www.ostriches.org/factor.html#head}}</ref>
*The flight mechanism and aerodynamics of the [[bumblebee]] (as well as other insects) are actually [[Insect_flight#Basic_aerodynamics|quite well understood]], in spite of the urban legend that calculations show [[Bumblebee#Myths|that they should not be able to fly]]. In the 1930s a German scientist, using flawed techniques, indeed postulated that bumblebees theoretically should not be able to fly,<ref>[http://naturenet.net/blogs/index.php/2008/01/04/can_bees_fly Can bees fly? The Virtual Ranger]</ref> although he later retracted the suggestion. However, the theory became generalized to the false notion that "scientists think that bumblebees should not be able to fly."
*[[Shark]]s can actually suffer from [[cancer]]. The myth that sharks do not get cancer was spread by the [[1992]] book ''Sharks Don't Get Cancer'' by I. William Lane and used to sell extracts of shark [[cartilage]] as cancer prevention treatments. Reports of [[carcinoma]]s in sharks exist, and current data do not allow any speculation about the incidence of tumors in sharks.<ref>{{cite journal |last1=Ostrander |first1=G. K. |last2=Cheng |first2=KC |last3=Wolf |first3=JC |last4=Wolfe |first4=MJ |title=Shark Cartilage, Cancer and the Growing Threat of Pseudoscience |journal=Cancer Research |volume=64 |issue=23 |pages=8485 |year=2004 |pmid=15574750 |doi=10.1158/0008-5472.CAN-04-2260}}</ref>
*It is not harmful to baby birds to pick them up and return them to their nests, despite the common belief that doing so will cause the mother to reject them.<ref>{{cite news|last=Lollar|first=Michael|title=Fine feathered infirmary for sick songbirds |url=http://www.knoxnews.com/news/2008/jun/16/fine-feathered-infirmary-for-sick-songbirds/|accessdate=12 January 2011|newspaper=Knoxs News|date=16 June 2008}}</ref><ref>{{Cite web|url=http://www.snopes.com/critters/wild/babybird.asp|title=Rejected baby birds|publisher=|date=|accessdate=2011-01-22|archiveurl=}}</ref>
*Bulls are not enraged by the color red, used in capes by professional [[matador]]s. Cattle are [[Dichromacy|dichromats]], so red does not stand out as a bright color. It is not the color of the cape that angers the bull, but rather the movement of the fabric that irritates the bull and incites it to charge.<ref>{{Cite web|url=http://www.itla.net/index.cfm?sec=Longhorn_Information&con=handling|title=Longhorn_Information - handling|publisher=ITLA|date=|accessdate=2010-06-23}}</ref><ref>{{Cite web|url=http://iacuc.tennessee.edu/pdf/Policies-AnimalCare/Cattle-BasicCare.pdf|title=Cattle – Basic Care|publisher=|date=|accessdate=2010-06-23|archiveurl=http://web.archive.org/web/20080625012822/http://iacuc.tennessee.edu/pdf/Policies-AnimalCare/Cattle-BasicCare.pdf|archivedate=2008-06-25}}</ref><ref>{{Cite book|url=http://books.google.com/books?id=GhmrNYJhcrIC&pg=PA45&lpg=PA45&dq=cattle+dichromat&source=bl&ots=OcnSVYzjFx&sig=CRNNUtgrKU5ha7fOyETsfi7lJ_Y&hl=en&ei=uBJDTZ3sJ4P-8AaahKm3AQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBMQ6AEwAA#v=onepage&q&f=false|title=Livestock handleing and transport|publisher=CABI|year=2007|accessdate=2011-01-28}}</ref>

====Evolution====
{{See|Objections to evolution|Introduction to evolution}}
[[File:Palais de la Decouverte Tyrannosaurus rex p1050042.jpg|thumb|left|230px|''[[Tyrannosaurus rex]]''. Non-[[bird|avian]] [[dinosaur]]s died out in the [[Cretaceous–Tertiary extinction event]] at the end of the [[Cretaceous]] period.]]
*The word ''[[theory]]'' in ''the theory of evolution'' does not imply mainstream scientific doubt regarding its validity; the concepts of ''theory'' and ''hypothesis'' have specific meanings in a scientific context. While ''theory'' in colloquial usage may denote a hunch or conjecture, a ''[[scientific theory]]'' is a set of principles that explains ''observable phenomena'' in [[naturalism (philosophy)|natural]] terms.<ref>{{Cite web|url=https://www.msu.edu/~pennock5/research/papers/Pennock_TeachingEvoNatureSci.pdf|format=PDF|title=Evolutionary Science and Society: Educating a New Generation (TOC)|publisher=MSU.edu|work=Revised Proceedings of the BSCS, AIBS Symposium|month=November |year=2004|accessdate=2011-01-13}}{{Page needed|date=January 2011}}</ref><ref>{{Cite web|url=http://chandra.harvard.edu/chronicle/0308/theo/index.html|title=It Is Not Just a Theory… It Is a Theory!|date=July 7, 2008|publisher=[[Harvard-Smithsonian Center for Astrophysics]]|work=Chandra Chronicles|accessdate=2009-04-08}}</ref> Evolution is a theory in the same sense as [[germ theory]], [[gravitation]], or [[plate tectonics]].<ref>{{Cite web|url=http://evoled.dbs.umt.edu/lessons/miscon.htm#3|title=Misconceptions about the Nature of Science|publisher=[[University of Montana]], Div. Biological Sciences|work=UMT.edu|accessdate=2009-04-08}}</ref> {{see also|Objections to evolution#Status as a theory}} [[File:Aegyptopithecus NT.jpg|thumb|A reconstruction of ''[[Aegyptopithecus]]'', a primate—and not a monkey—predating the split between the human and [[Old World monkey]] lineages in [[human evolution]].]]
*Evolution does not claim humans evolved from [[monkey]]s,<ref name="pbs_evolution_faq">{{Cite web|url=http://www.pbs.org/wgbh/evolution/library/faq/cat02.html#Q01|title=Evolution: Frequently Asked Questions|publisher=PBS.org|date=|accessdate=2009-08-29}}</ref> [[chimpanzee]]s<ref>{{cite news|first=Amy |last=Harmon, New York Times|url=http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/08/30/MNSK12HD6J.DTL|title=Teaching evolution to young Christian skeptics|publisher=San Francisco Chronicle|date=August 31, 2008|accessdate=2009-08-29}}</ref> or any other modern-day primates. Instead, humans and monkeys share a [[common descent|common ancestor]] that lived about 40 million years ago.<ref>{{cite book|title=Primates in Perspective|author=Hartwig, W.|chapter=Primate Evolution |editor=Campbell, C., Fuentes, A., MacKinnon, K., Panger, M. & Bearder, S.|year=2007|publisher=[[Oxford University Press]]|isbn=978-0-19-517133-4}}</ref> This common ancestor diverged into separate lineages, one evolving into so-called [[New World monkey]]s and the other into [[Old World monkey]]s and [[ape]]s.<ref>{{MSW3 Groves|pages=111–184|id=12100001}}</ref> Humans are part of the [[Hominidae]] (great ape) family, which also includes chimpanzees, gorillas, and orangutans. Similarly, the common ancestor of humans and chimpanzees, which lived between 5 and 8 million years ago, evolved into two lineages, one eventually becoming modern humans and the other the two extant [[chimpanzee]] species.<ref name="pbs_evolution_faq" />
*Evolution is not a progression from inferior to superior organisms, and it also does not necessarily result in an [[evolution of complexity|increase in complexity]]. A population can evolve to become simpler, having a smaller [[genome]], but ''[[devolution (biology)|devolution]]'' is a [[misnomer]].<ref>{{cite web|url=http://www.scientificamerican.com/article.cfm?id=is-the-human-race-evolvin |title=Is the human race evolving or devolving? |date=July 20, 1998 | publisher=''[[Scientific American]]'' |first=|last=}} see also [[biological devolution]].</ref><ref name="pmid11893328">{{cite journal |last1=Moran |first1=Nancy A. |title=Microbial MinimalismGenome Reduction in Bacterial Pathogens |journal=Cell |volume=108 |issue=5 |pages=583–6 |year=2002 |pmid=11893328 |doi=10.1016/S0092-8674(02)00665-7}}</ref>
*It is a common misconception, even among adults, that humans and [[dinosaur]]s coexisted: According to the [[California Academy of Sciences]], around 41% of U.S. adults mistakenly believe they co-existed.<ref name=science_daily>{{cite web|url=http://www.sciencedaily.com/releases/2009/03/090312115133.htm |title=American Adults Flunk Basic Science |publisher=''[[Science Daily]]''|date= March 13, 2009}}</ref> The last of the dinosaurs died around 65 million years ago, after the [[Cretaceous–Tertiary extinction event]], whereas the earliest ''[[Homo]]'' genus (humans) evolved between 2.3 and 2.4 million years ago.
*Evolution does not violate the [[Second Law of Thermodynamics]]. A common argument against evolution is that entropy, according to the Second Law of Thermodynamics, increases over time, and thus evolution could not produce increased [[evolution of complexity|complexity]]. However, the law does not refer to complexity and only applies to closed systems,<ref>{{cite web| url=http://www.talkorigins.org/faqs/faq-misconceptions.html |title=Five Major Misconceptions about Evolution |year=2003 |first=Mark |last=Isaak| publisher=The Talk Origins Archive|work=TalkOrigins.org}}</ref> which the Earth is not, as it absorbs and radiates the Sun's energy.<ref>{{cite web |url= http://physics.gmu.edu/~roerter/EvolutionEntropy.htm |title=Does Life On Earth Violate the Second Law of Thermodynamics? |first=Robert N. |last=Oerter |publisher=[[George Mason University]] Dept. of Physics and Astronomy |accessdate=2011-01-11}}</ref>
*Evolution does not "plan" to improve organism's fitness to survive.<ref>{{cite web|url=http://evolution.berkeley.edu/evolibrary/misconceptions_faq.php#a4|title=Understanding evolution: Misconceptions about evolution and the mechanisms of evolution}} Misconception: "Natural selection involves organisms 'trying' to adapt."</ref><ref>{{cite web|url=http://evolution.berkeley.edu/evolibrary/misconceptions_faq.php#a5|title=Understanding evolution: Misconceptions about evolution and the mechanisms of evolution}} Misconception:"Natural selection gives organisms what they 'need.'"</ref> For example, an incorrect way to describe Giraffe evolution is to say that giraffe necks grew longer over time because they needed to reach tall trees. Evolution doesn't "see" a need and respond to it. A mutation resulting in longer necks would be more likely to benefit an animal in an area with tall trees than an area with short trees, and thus enhance the chance of the animal surviving to pass on its longer-necked genes. Tall trees could not cause the mutation nor would they cause a higher percentage of animals to be born with longer necks.

===Chemistry===
[[File:Blowing.jpg|thumb|left|250px|Glass manufacturing in older eras was a slower process, which often resulted in unevenness and impurities when finished in its solid state. Varying thickness throughout older window panes is the result of these impurities, not due to movement of the glass over time.]]
*[[Glass]] is not a high-[[viscosity]] liquid at room temperature: it is an [[amorphous solid]], although it does have some chemical properties normally associated with liquids. Panes of [[stained glass]] windows often have thicker glass at the bottom than at the top, and this has been cited as an example of the slow flow of glass over centuries. However, this unevenness is due to the window manufacturing processes used in earlier eras, which produced glass panes that were unevenly thick at the time of their installation. Normally the thick end of glass would be installed at the bottom of the frame, but it is also common to find old windows where the thicker end has been installed to the sides or the top. In fact, the lead frames of the windows are less viscous than the panes, and if glass was indeed a slow moving liquid, the panes would warp at a higher degree.<ref>{{Cite news|url=http://www.nytimes.com/2008/07/29/science/29glass.html|work=The New York Times|title=The Nature of Glass Remains Anything but Clear|first=Kenneth|last=Chang|date=2008-07-29|accessdate=2010-04-04}}</ref><ref>{{Cite web|url=http://www.glassnotes.com/WindowPanes.html|title=Does Glass Flow|publisher=Glassnotes.com|date=1998-05-30|accessdate=2009-08-29}}</ref>

===Human body and health===
{{see also|Misconceptions about HIV and AIDS}}

====The senses====
[[Image:Taste buds.svg|thumb|right|100px|An '''incorrect''' [[tongue map|map of the tongue]] showing zones which taste [[Bitter_(taste)#Bitter|bitter]] (1), [[Sour#Sour|sour]] (2), [[Taste#Salty|salty]] (3) and [[Sweetness|sweet]] (4). In reality, all zones can sense all tastes.]]
*Different [[taste]]s can be detected on all parts of the [[tongue]] by [[taste bud]]s,<ref>{{Cite journal|author=Huang AL, Chen X, Hoon MA, ''et al.''|title=The cells and logic for mammalian sour taste detection|journal=Nature|volume=442|issue=7105|pages=934–8|year=2006|month=August|pmid=16929298|pmc=1571047|doi=10.1038/nature05084}}</ref> with slightly increased sensitivities in different locations depending on the person, contrary to the popular belief that specific tastes only correspond to specific mapped sites on the tongue.<ref>{{Cite web|url=http://www.asha.org/Publications/leader/2002/021022/f021022a.htm|title=Beyond the Tongue Map|publisher=Asha.org|date=2002-10-22|accessdate=2009-08-29}}</ref> The original [[tongue map]] was based on a mistranslation of a 1901 German thesis<ref>Hänig, David P., 1901. [http://vlp.mpiwg-berlin.mpg.de/library/data/lit4562 Zur Psychophysik des Geschmackssinnes.] Philosophische Studien, 17: 576–623.</ref> by [[Edwin Boring]]. In addition, there are not 4 but 5 primary tastes. In addition to [[Bitter_(taste)#Bitter|bitter]], [[Sour#Sour|sour]], [[Taste#Salty|salty]], and [[Sweetness|sweet]], humans have taste receptors for [[umami]], which is a savory or meaty taste.<ref>{{cite book |title=Food Science and Technology |last=Campbell-Platt |first=Geoffrey |url=http://books.google.com/?id=E7GXHploJasC&lpg=PA31&pg=PA31 |year=2009 |publisher=Wiley |isbn=9780632064212 |page=31 |accessdate=2011-01-05}}</ref><ref>{{cite web |url=http://www.rtc.edu/programs/generaleducation/biology/biology220/files/Senses_notes.pdf |title=Senses Notes |accessdate=2011-01-13}}</ref><ref>{{cite web |url=http://www.npr.org/templates/story/story.php?storyId=15819485 |title=Sweet, Sour, Salty, Bitter … and Umami |author=Robert Krulwich |date=5 November 2007 |work=Krulwich Wonders, an NPR Science Blog |publisher=NPR |accessdate=2011-01-13}}</ref>
* Humans have more than five [[senses]]. Although definitions vary, the actual number ranges from 9 to more than 20. In addition to [[visual perception|sight]], [[olfaction|smell]], [[taste]], [[somatosensory system|touch]], and [[hearing (sense)|hearing]], which were the senses identified by [[Aristotle]], humans can sense balance and acceleration ([[equilibrioception]]), pain ([[nociception]]), body and limb position ([[proprioception]] or kinesthetic sense), and relative temperature ([[thermoception]]).<ref>{{cite web |url=http://harvardmedicine.hms.harvard.edu/fascinoma/fivesenses/beyond/extra.php |title=Extra Sensory Perceptions |author=Jessica Cerretani |date=Spring 2010 |work=Harvard Medicine |publisher=Harvard College |accessdate=2011-01-13}}</ref> Other senses sometimes identified are the sense of time, itching, pressure, hunger, thirst, fullness of the stomach, need to urinate, need to defecate, and blood [[carbon dioxide]] levels.<ref>{{cite web |url=http://health.howstuffworks.com/mental-health/human-nature/perception/question242.htm |title=How many senses does a human being have? |work=Discovery Health |publisher=Discovery Communications Inc. |accessdate=2011-01-13}}</ref><ref>{{cite web |url=http://www.cliffsnotes.com/study_guide/Human-Senses.topicArticleId-8741,articleId-8725.html |title=Biology: Human Senses |work=CliffNotes |publisher=Wiley Publishing, Inc |accessdate=2011-01-13}}</ref>

====Skin and hair====
*Shaving does not cause [[terminal hair]] to grow back thicker or coarser or darker. This belief is because hair that has never been cut has a tapered end, whereas, after cutting, there is no taper. Thus, it appears thicker, and feels coarser due to the sharper, unworn edges. The fact that shorter hairs are "harder" (less flexible) than longer hairs also contributes to this effect.<ref>{{Cite web|url=http://snopes.com/oldwives/hairgrow.asp|title=Shaved Hair Grows Darker|publisher=snopes.com|date=|accessdate=2009-08-29}}</ref> Hair can also appear darker after it grows back because hair that has never been cut is often lighter due to sun exposure.
*Hair and fingernails do not continue to grow after a person dies. Rather, the skin dries and shrinks away from the bases of hairs and nails, giving the appearance of growth.<ref>{{Cite book|last=Graham-Brown|first=Robin|coauthors=Tony Burns|title=Lecture Notes on Dermatology|publisher=Blackwell|year=2007|page=6|isbn=1-4051-3977-3}}</ref>
*Hair care products cannot as such "repair" [[Trichoptilosis|split ends]] and damaged hair. They can, however, prevent damage from occurring in the first place, smooth down the cuticle in a glue-like fashion so that it appears repaired and generally make hair appear in better condition.<ref>http://beauty.about.com/library/bltips531.htm About.com</ref><ref>http://wwweHow.com/how-does_4569485_hair-conditioner-work.html How does hair conditioner work</ref><ref>{{Cite web|title=disabled-world.com|url=http://www.disabled-world.com/health/dermatology/hair/hair-care.php|accessdate=2009-04-13}}</ref><ref>{{Cite news|title=cbc.ca|url=http://www.cbc.ca/streetcents/features/front_question_of_the_week.html |title=Question: What is up with colour-enhancing shampoos? Do they work?|accessdate=2010-01-13|publisher=CBC News|work=CBC.ca}}</ref><ref>{{Cite web|title=Hair Myths|url=http://www.glamour.com/beauty/2008/09/hair-myths|publisher=Glamour.com| accessdate=2009-04-13}}</ref>

====Nutrition, food, and drink====
*Eight glasses of water a day are not necessary to maintain health.<ref name=NPR/><ref name="9ThingsToStopWorryingAbout">{{cite web|url=http://health.msn.com/healthy-living/slideshow.aspx?cp-documentid=100268897&imageindex=2|title=9 Things to Stop Worrying About|author=Dorothy Foltz-Gray|publisher=[[MSN]]|accessdate=2011-02-02}}</ref> Consuming juice, tea, milk, fruits and vegetables also keeps a person hydrated.<ref name="9ThingsToStopWorryingAbout"/>
*Sugar does not cause hyperactivity in children.<ref name="festive myths">{{Cite journal|author=Vreeman RC, Carroll AE|title=Festive medical myths|journal=BMJ|volume=337|issue=|pages=a2769|year=2008|pmid=19091758|doi=10.1136/bmj.a2769}}</ref> [[Double-blind test|Double-blind trials]] have shown no difference in behavior between children given sugar-full or sugar-free diets, even in studies specifically looking at children with [[Attention deficit hyperactivity disorder|attention-deficit/hyperactivity disorder]] or those considered "sensitive" to sugar. The difference in behaviour proved to be psychological.<ref>{{Cite book|last=Fullerton-Smith|first=Jill|title=The Truth About Food|publisher=Bloomsbury|year=2007|pages=115–117|isbn=9780747586852|quote="Most parents assume that children plus sugary foods equals raucous and uncontrollable behaviour.[…] according to nutrition experts, the belief that children experience a "sugar high" is a myth."}}</ref>
*Alcohol does not in fact make one warmer.<ref>{{cite news|url=http://news.google.com/newspapers?id=kG5BAAAAIBAJ&sjid=QKkMAAAAIBAJ&pg=5953,3984482|title=Popular Misconceptions Regarding Intoxication|last=Brandstadt|first=William G.|date=December 19, 1967|work=Middlesboro Daily News|accessdate=2011-01-13}}</ref><ref>{{cite news|url=http://news.google.com/newspapers?id=Y7QOAAAAIBAJ&sjid=voIDAAAAIBAJ&pg=6314,2739204|title=Hypothermia main outdoors threat|last=Pierson|first=Rebecca|date=December 9, 2004|work=Elizabethton Star|accessdate=2011-01-13}}</ref><ref>{{cite news|url=http://news.google.com/newspapers?id=6QxOAAAAIBAJ&sjid=3q0DAAAAIBAJ&pg=6238,1782448|title=Writer Tells Of Alcohol Dangers, Misconceptions|last=Seixas|first=Judy|date=April 15, 1977|work=The Virgin Islands Daily News|accessdate=2011-01-13}}</ref> The reason that alcoholic drinks create the sensation of warmth is that they cause blood vessels to dilate and stimulate nerve endings near the surface of the skin with an influx of warm blood. This can actually result in making the core body temperature lower, as it allows for easier heat exchange with a cold external environment.<ref>{{Cite web|url=http://firstaid.about.com/od/heatcoldexposur1/f/07_alcohol_warm.htm|title=Alcohol for Warmth}}</ref>
*It is a common misconception that alcohol kills brain cells.<ref name="StudyFindsAlcoholDoesntKillOffBrainCells">{{cite web|url=http://www.news.com.au/study-finds-alcohol-doesnt-kill-off-brain-cells/story-e6frfkp9-1111113923217|title=Study finds alcohol doesn't kill off brain cells | News.com.au|publisher=[[News Limited]]|accessdate=2011-01-08}}</ref><ref name="BrainMythsBusted">{{cite web|url=http://health.msn.com/health-topics/articlepage.aspx?ucpg=3&pgnew=False&cp-documentid=100236538&ucsort=4&=|title=Brain Myths—Busted|author=Rich Maloof|publisher=[[MSN]]|accessdate=2011-01-08}}</ref> Early temperance writers promoted the idea that drinking causes brain cells to die (as well as the assertion that the alcohol in the blood stream could cause people to catch fire and burn alive).<ref name="DoesDrinkingAlcoholKillBrainCells">{{cite web|url=http://www2.potsdam.edu/hansondj/HealthIssues/1103162109.html|title=Does Drinking Alcohol Kill Brain Cells?|author=David J. Hanson|publisher=[[State University of New York]]|accessdate=2011-01-08}}</ref> According to [[University of Queensland|Queensland Brain Institute]] director Professor Perry Bartlett, there is no evidence that drinking alcohol leads directly to the death of brain cells.<ref name="StudyFindsAlcoholDoesntKillOffBrainCells" /> In fact, alcohol has positive health benefits when used moderately<ref name="StudyFindsAlcoholDoesntKillOffBrainCells" /><ref name="DoesDrinkingAlcoholKillBrainCells" /> and new brain cells are generated on a daily basis.<ref name="StudyFindsAlcoholDoesntKillOffBrainCells" /> Alcohol can lead ''indirectly'' to the death of brain cells in chronic, heavy alcohol users whose brains have adapted to the effects of alcohol, where abrupt cessation following heavy use can cause [[excitotoxicity]] leading to cellular death in multiple areas of the brain.<ref>{{cite journal|author=Lovinger, D. M.|year=1993| title=Excitotoxicity and Alcohol-Related Brain Damage |journal=Alcoholism: Clinical and Experimental Research |volume=17 |pages=19–27 |doi=10.1111/j.1530-0277.1993.tb00720.x}}</ref>
*It is a common misconception that a [[vegetarian]] or [[vegan]] diet cannot provide enough protein.<ref name="VegetarianCommonMyths">{{cite web| url=http://evolvingwellness.com/posts/405/5-common-myths-about-vegetarians/| title=Common5 Common Myths about Vegetarians}}</ref><ref name="ExplodingProteinMyth">{{cite web| url=http://www.skrewtips.com/2007/09/18/exploding-the-protein-myth/|title=Exploding the Protein Myth}}</ref><ref name="AceFitness">{{cite web| url=http://www.acefitness.org/blog/86/are-vegetarian-diets-safe/| title=Are vegetarian diets safe?}}</ref><ref name="PCRM">{{cite web| url=http://www.pcrm.org/health/veginfo/protein.html|title=How Can I Get Enough Protein? The Protein Myth }}</ref> In fact, typical protein intakes of [[Ovo-lacto vegetarianism|ovo-lacto vegetarians]] and of [[vegan]]s meet and exceed requirements.<ref name="DieticiansGuide">{{cite book |title=The dietitian's guide to vegetarian diets |last=Messina |first=Virginia | coauthors=Reed Mangles, Mark Messina |year=2004 |publisher=Jones and Bartlett Publishers |location=Sudbury, MA |isbn=978-0763732417 |url=ISBN 978-0763732417}}</ref><ref name=akers>Akers, Keith: ''[http://www.compassionatespirit.com/protein.htm But How Do You Get Enough Protein?]''. Compassionate Spirit. Retrieved 25 June 2010.</ref> While lower in protein than non-vegetarian diets, adequate but low protein diets have been shown to be beneficial against cancer.<ref>Food Navigator USA: [http://www.foodnavigator-usa.com/news/ng.asp?n=72611-protein-cancer ''Low-protein diets could protect against cancer, says new study'']. 7 December 2006. Retrieved 4 January 2007.</ref> A non-vegetarian diet high in protein such as a typical diet in the United States in fact has been shown to be linked to several diseases including [[osteoporosis]], [[cancer]], impaired [[kidney]] function, and [[heart disease]].<ref name="PCRM"/>
*Bottled water, vitamin-enriched water, and sparkling water are not healthier than tap water.<ref name=NPR>{{cite news |title=Five Myths About Drinking Water |author=Aubrey, Allison |url=http://www.npr.org/templates/story/story.php?storyId=89323934 |newspaper=National Public Radio |date=April 3, 2008 |accessdate=January 16, 2011}}</ref> In fact, many studies have shown that bottled water often contains mixtures of bacteria, fertilizers, and a variety of pollutants.<ref>{{cite news |title=Bottled Water Quality Investigation: 10 Major Brands, 38 Pollutants|author=Olga Naidenko, PhD, Senior Scientist; Nneka Leiba, MPH, Researcher; Renee Sharp, MS, Senior Scientist; Jane Houlihan, MSCE, Vice President for Research|url=http://www.ewg.org/reports/BottledWater/Bottled-Water-Quality-Investigation|newspaper=Environmental Working Group |date=October 2008 |accessdate=January 20, 2011}}</ref>

====Human sexuality====
*A popular myth regarding [[human sexuality]] is that men think about sex every seven seconds. In reality, there is no scientific way of measuring such a thing and, as far as researchers can tell, this statistic greatly exaggerates the frequency of sexual thoughts.<ref>{{Cite web|url=http://www.livescience.com/bestimg/index.php?url=myths_men_sex_03.jpg&cat=myths|title=LiveScience.com: The Most Popular Myths in Science|publisher=LiveScience|date=|accessdate=2010-06-23}}</ref><ref>{{Cite news|last=Ahuja|first=Anjana|title=Every 7 seconds? That's a fantasy|url=http://www.timesonline.co.uk/tol/life_and_style/article723673.ece|accessdate=18 June 2010|newspaper=The Times|date=1 February 2006|location=London}}</ref><ref>{{Cite web|last=Mikkelson|first=Barbara|title=Daydream Deceiver|url=http://www.snopes.com/science/stats/thinksex.asp|work=Snopes.com|accessdate=18 June 2010}}</ref>
*Another popular myth is that having sex in the days leading up to a sporting event or contest is detrimental to performance. Numerous studies have shown that there is no physiological basis to this myth.<ref>{{Cite web
|url=http://www.nature.com/news/2006/060609/full/news060605-16.html
|title=Sex before the big game?
|publisher=Nature
|date=2006-06-09|accessdate=2011-01-16}}</ref> Additionally, it has been demonstrated that sex during the 24 hours prior to sports activity can elevate the levels of [[testosterone]] in males, which potentially could enhance their performance.<ref>{{Cite web|title=Sex and Sports: Should Athletes Abstain Before Big Events?|url=http://news.nationalgeographic.com/news/2006/02/0222_060222_sex.html
|publisher=National Geographic|date=2006-02-22|accessdate=2011-01-16}}</ref>

====The brain====
*Mental abilities are not absolutely separated into the left and right [[cerebral hemisphere]]s of the brain.<ref name="Westen 2006">Westen et al. 2006 "Psychology: Australian and New Zealand edition" John Wiley p.107</ref> Some mental functions such as [[Speech communication|speech]] and [[language]] (cf. [[Broca's area]], [[Wernicke's area]]) tend to activate [[lateralization of brain function|one hemisphere of the brain more than the other]], in some kinds of tasks. If one hemisphere is damaged at a very early age, however, these functions can often be recovered in part or even in full by the other hemisphere (see [[Neuroplasticity]]). Other abilities such as [[somatic nervous system|motor control]], memory, and general reasoning are served equally by the two hemispheres.<ref>{{cite journal |last1=Goswami |first1=U |title=Neuroscience and education: from research to practice? |journal=Nature reviews. Neuroscience |volume=7 |issue=5 |pages=406–11 |year=2006 |pmid=16607400 |doi=10.1038/nrn1907}}</ref> [[Image:Gyrus Dentatus 40x.jpg|thumb|left|250px|Golgi-stained neurons in human hippocampal tissue. It is commonly believed that humans will not grow new brain cells, but research has shown that some neurons can reform in humans.]]
*Until very recently medical experts believed that humans were born with all of the brain cells they would ever have.<ref>{{cite web|url=http://www.sfn.org/index.aspx?pagename=brainbriefings_adult_neurogenesis|name=Socity for Neuroscience|title=Adult Neurogenisis}}</ref> However, we now know that new [[neuron]]s can be created in the [[postnatal]] brain. Researchers have observed adult neurogenesis in [[bird|avians]],<ref>{{cite journal|author=Goldman SA, Nottebohm F|title=Neuronal production, migration, and differentiation in a vocal control nucleus of the adult female canary brain|journal=Proc Natl Acad Sci U S A.|volume=80|issue=8|pages=2390–4|year=1983|month=April|pmid=6572982|pmc=393826|doi=10.1073/pnas.80.8.2390|url=http://www.pnas.org/cgi/pmidlookup?view=long&pmid=6572982}}</ref> [[primates|Old World Primates]],<ref>{{cite journal |doi=10.1073/pnas.96.9.5263 |last1=Gould |first1=E |last2=Reeves |first2=AJ |last3=Fallah |first3=M |last4=Tanapat |first4=P |last5=Gross |first5=CG |last6=Fuchs |first6=E |title=Hippocampal neurogenesis in adult Old World primates |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=96 |issue=9 |pages=5263–7 |year=1999 |pmid=10220454 |pmc=21852}}</ref> and humans.<ref>{{cite journal |last1=Eriksson |first1=Peter S. |last2=Perfilieva |first2=Ekaterina |last3=Björk-Eriksson |first3=Thomas |last4=Alborn |first4=Ann-Marie |last5=Nordborg |first5=Claes |last6=Peterson |first6=Daniel A. |last7=Gage |first7=Fred H. |title=Neurogenesis in the adult human hippocampus |journal=Nature Medicine |volume=4 |issue=11 |pages=1313–7 |year=1998 |pmid=9809557 |doi=10.1038/3305}}</ref> Adults of these species retain multipotent (see [[cell potency]]) neural stem cells in the [[subventricular zone]] of the [[lateral ventricles]] and [[subgranular zone]] of the [[dentate gyrus]].<ref>{{cite journal |last1=Reh |first1=Thomas A. |last2=Ponti |first2=Giovanna |last3=Peretto |first3=Paolo |last4=Bonfanti |first4=Luca |title=Genesis of Neuronal and Glial Progenitors in the Cerebellar Cortex of Peripuberal and Adult Rabbits |journal=PLoS ONE |volume=3 |issue=6 |pages=e2366 |year=2008 |pmid=18523645 |pmc=2396292 |doi=10.1371/journal.pone.0002366}}</ref><ref>{{cite journal |last1=Zhao |first1=Chunmei |last2=Deng |first2=Wei |last3=Gage |first3=Fred H. |title=Mechanisms and Functional Implications of Adult Neurogenesis |journal=Cell |volume=132 |issue=4 |pages=645–60 |year=2008 |pmid=18295581 |doi=10.1016/j.cell.2008.01.033}}</ref> The newborn neurons generated in these areas migrate to the [[olfactory bulb]] and the [[dentate gyrus]], respectively, and are believed to integrate into existing neural circuits. However, the function and physiological significance of adult-born neurons remains unclear. Some studies have suggested that post-natal neurogenesis also occurs in the [[neocortex]],<ref>{{cite journal |doi=10.1126/science.286.5439.548 |last1=Gould |first1=E |last2=Reeves |first2=AJ |last3=Graziano |first3=MS |last4=Gross |first4=CG |title=Neurogenesis in the neocortex of adult primates |journal=Science |volume=286 |issue=5439 |pages=548–52 |year=1999 |pmid=10521353}}</ref><ref>{{cite journal |last1=Zhao |first1=M |last2=Momma |first2=S |last3=Delfani |first3=K |last4=Carlen |first4=M |last5=Cassidy |first5=RM |last6=Johansson |first6=CB |last7=Brismar |first7=H |last8=Shupliakov |first8=O |last9=Frisen |first9=J |title=Evidence for neurogenesis in the adult mammalian substantia nigra |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=100 |issue=13 |pages=7925–30 |year=2003 |pmid=12792021 |pmc=164689 |doi=10.1073/pnas.1131955100}}</ref><ref>{{cite journal |doi=10.1007/s100249900120 |last1=Shankle |first1=WR |last2=Rafii |first2=MS |last3=Landing |first3=BH |last4=Fallon |first4=JH |title=Approximate doubling of numbers of neurons in postnatal human cerebral cortex and in 35 specific cytoarchitectural areas from birth to 72 months |journal=Pediatric and developmental pathology |volume=2 |issue=3 |pages=244–59 |year=1999 |pmid=10191348}}</ref> an idea that is disputed.<ref name="pmid11826088">{{cite journal |last1=Rakic |first1=P |title=Adult neurogenesis in mammals: an identity crisis |journal=The Journal of neuroscience |volume=22 |issue=3 |pages=614–8 |year=2002 |pmid=11826088}}</ref>
*[[Vaccine]]s do not cause [[autism]]. [[MMR vaccine controversy|Fraudulent research]] by [[Andrew Wakefield]] claimed a connection. The results could not be [[Reproducibility|reproduced]]. Subsequently the research was shown to be flawed and fraudulent.<ref>{{cite web|url=http://www.bmj.com/content/342/bmj.c7452.full|title=British Medical Journal: Wakefield’s article linking MMR vaccine and autism was fraudulent|accessdate=2011-01-05}}</ref>
*People do not use [[10% of brain myth|only ten percent of their brains]]. While it is true that a small minority of neurons in the brain are actively firing at any one time, the inactive neurons are important too.<ref>{{Cite web|url=http://www.snopes.com/science/stats/10percent.asp|title=Snopes on brains|publisher=Snopes.com|date=|accessdate=2009-08-29}}</ref><ref>{{Cite journal|last=Radford|first=Benjamin|date=March/April 1999|title=The Ten-Percent Myth|journal=Skeptical Inquirer|publisher=Committee for the Scientific Investigation of Claims of the Paranormal|issn=0194-6730|url=http://www.csicop.org/si/show/the_ten-percent_myth/|accessdate=2009-04-15|quote=It's the old myth heard time and again about how people use only ten percent of their brains}}</ref> This myth has been commonplace in American culture at least as far back as the start of the 20th century, and was attributed to [[William James]], who apparently used the expression metaphorically.<ref name="beyersteinbrain">{{Cite book|last=Beyerstein|first=Barry L.|title=Mind Myths: Exploring Popular Assumptions About the Mind and BRain|editor=Sergio Della Sala|publisher=Wiley|year=1999|pages=3–24|chapter=Whence Cometh the Myth that We Only Use 10% of our Brains?|isbn=0471983039}}</ref> Some findings of brain science (such as the high ratio of [[glial cell]]s to [[neurons]]) have been mistakenly read as providing support for the myth.<ref name="beyersteinbrain"/>

====Disease====
*It is a common misconception that those suffering from flu or cold congestion should avoid dairy because it may increase mucus production. Drinking milk and/or consuming other dairy products does not increase mucus production.<ref>{{cite journal |last1=Pinnock |first1=CB |last2=Graham |first2=NM |last3=Mylvaganam |first3=A |last4=Douglas |first4=RM |title=Relationship between milk intake and mucus production in adult volunteers challenged with rhinovirus-2 |journal=The American review of respiratory disease |volume=141 |issue=2 |pages=352–6 |year=1990 |pmid=2154152}}</ref><ref>{{cite book|title=Handbook of pediatric nutrition |author1=Patricia Queen Samour |author2=Kathy King Helm |publisher=Jones & Bartlett Learning |year=2005 |isbn=0763783560 |url=http://books.google.com/?id=J8Xgyvr9038C&pg=PA337&lpg=PA337&dq=milk+mucus+misconception#v=onepage&q=milk%20mucus%20misconception&f=false}}</ref>
*[[Wart]]s on human skin are caused by viruses that are unique to humans ([[human papillomavirus]]). Humans cannot catch warts from [[toad]]s or other animals; the bumps on a toad are not warts.<ref>{{Cite web|author=London Drugs|url=http://www.londondrugs.com/Cultures/en-US/FocusOnHealth/Fall2002/Warts.htm|title=''Putting an End to Warts''|publisher=www.londondrugs.com|date=|accessdate=2009-08-29}}</ref>
*[[Fever]] does not harm the brain or the body, though it does increase the need for fluids. Fever does not cause brain damage or death in children if untreated. In fact, fever is normally a signal that the immune system is working well. Extreme fever (hyperpyrexia, a body temperature above 41.5 °C or 106.7 °F) is, however, harmful if left untreated.<ref name=EM01>{{cite journal |author=McGugan EA |title=Hyperpyrexia in the emergency department |journal=Emerg Med (Fremantle) |volume=13 |issue=1 |pages=116–20 |year=2001 |month=March |pmid=11476402 |doi= 10.1046/j.1442-2026.2001.00189.x|url=}}</ref><ref>{{cite news|title=Lifting a Veil of Fear to See a Few Benefits of Fever |work=New York Times |date=January 10, 2011|url=http://www.nytimes.com/2011/01/11/health/11klass.html |author=Perri Klaus}}</ref><ref>{{cite journal |title=Fever Phobia Revisited: Have Parental Misconceptions About Fever Changed in 20 Years? |journal=Pediatrics |date=June 6, 2001 |vol=107 |no=6 |date=June 2001|pages=1241–1246|author=Michael Crocetti, Nooshi Moghbeli, and Janet Serwint |url=http://pediatrics.aappublications.org/cgi/content/abstract/107/6/1241}}</ref><ref>{{cite journal |title=Fever Phobia: Misconceptions of Parents About Fevers |author= Barton D. Schmitt |journal=Am J Dis Child |year=1980 |vol=134 |no=2 |pages=176–181 |url=http://archpedi.ama-assn.org/cgi/content/abstract/134/2/176}}</ref>

====Miscellaneous====
*It is a common misconception that [[sleepwalking|sleepwalkers]] should not be awakened. While it is true that a person may be confused or disoriented for a short time after awakening, this does not cause them further harm. In contrast, sleepwalkers may injure themselves if they trip over objects or lose their balance while sleepwalking. Such injuries are common among sleepwalkers.<ref>{{Cite web|url=http://www.medicinenet.com/sleepwalking/article.htm|title=Sleepwalking: Causes, Symptoms, and Treatments|publisher=MedicineNet, Inc|accessdate=2009-05-10}}</ref><ref>{{Cite web|url=http://www.sleepfoundation.org/article/sleep-related-problems/sleepwalking|title=Sleepwalking|publisher=National Sleep Foundation|accessdate=2009-05-10}}</ref>
*In [[South Korea]], it is commonly believed that sleeping in a closed room with an [[electric fan]] running can be fatal. According to the Korean government, "In some cases, a fan turned on too long can cause death from [[asphyxia|suffocation]], [[hypothermia]], or fire from overheating." The Korea Consumer Protection Board issued a consumer safety alert recommending that electric fans be set on timers, direction changed and doors left open. Belief in [[fan death]] is common even among knowledgeable medical professionals in Korea. According to Yeon Dong-su, dean of Kwandong University's medical school, "If it is completely sealed, then in the current of an electric fan, the temperature can drop low enough to cause a person to die of hypothermia."<ref>{{cite press release|title=Beware of Summer Hazards!
|publisher=Korea Consumer Protection Board (KCPB)|date=2006-07-18|url=http://english.cpb.or.kr/user/bbs/code02_detail.php?av_jbno=2006071800002|archiveurl=http://web.archive.org/web/20070927051420/http://english.cpb.or.kr/user/bbs/code02_detail.php?av_jbno=2006071800002|archivedate=2007-09-27|accessdate=2009-09-05}}</ref><ref>{{Cite web|last=Surridge|first=Grant|title=Newspapers fan belief in urban myth|work=JoongAng Daily|date=2004-09-22|url=http://joongangdaily.joins.com/200409/22/200409222123324579900091009101.html|archiveurl=http://web.archive.org/web/20070110052746/http://joongangdaily.joins.com/200409/22/200409222123324579900091009101.html|archivedate=2007-01-10|publisher=Chicago Reader, Inc.|accessdate=2007-08-02 }}</ref><ref>{{Cite web|last=Adams|first=Cecil|title=Will sleeping in a closed room with an electric fan cause death?|work=The Straight Dope|date=1997-09-12|url=http://www.straightdope.com/columns/read/1245/will-sleeping-in-a-closed-room-with-an-electric-fan-cause-death|publisher=Chicago Reader, Inc.|accessdate=2007-08-02 }}</ref><ref>{{Cite web|last=Adams|first=Cecil|url=http://www.esquire.com/style/answer-fella/korean-fan-death-0209|title=Why Fan Death Is an Urban Myth|accessdate=2009-09-06}}</ref> Although an [[air conditioner]] transfers heat from the air and cools it, a fan moves air to increase the [[Evaporative_cooler#Physical_principles|evaporation of sweat]]. Due to [[Energy conversion efficiency|energy losses]], a fan will slowly heat a room.
*Although it is commonly believed that most body heat is lost through a person's head, heat loss through the head is not more significant than other parts of the body when naked.<ref>
{{cite journal
| doi = 10.1097/00000542-199010000-00011
| author = Sessler, D.I., Moayeri, A., et al.
| year = 1990
| title = Thermoregulatory vasoconstriction decreases cutaneous heat loss
| journal = Anesthesiology
| volume = 73
| issue = 4
| pages = 656
| issn = 0003-3022
| url = http://journals.lww.com/anesthesiology/Abstract/1990/10000/Thermoregulatory_Vasoconstriction_Decreases.11.aspx
| pmid = 2221434
}}</ref><ref>{{Cite news|author=Ian Sample, science correspondent|url=http://www.guardian.co.uk/science/2008/dec/17/medicalresearch-humanbehaviour|title=Scientists debunk myth that most heat is lost through head | Science|publisher=The Guardian|date=2008-12-18|accessdate=2010-06-23|location=London}}</ref> This may be a generalization of situations in which it is true, such as when the head is the only uncovered part of the body. For example, it has been shown that hats effectively prevent hypothermia in infants.<ref>{{cite journal| author = Stothers, JK| year=1981| title=Head insulation and heat loss in the newborn.| journal=British Medical Journal| volume=56| issue=7| pages=530| publisher=Royal Coll Paediatrics}}</ref>
*Eating less than an hour before swimming does not increase the risk of experiencing muscle [[cramp]]s or drowning. One study shows a correlation between alcohol consumption and drowning, but there is no evidence cited regarding stomach cramps or the consumption of food.<ref>{{Cite web|url=http://www.nytimes.com/2005/06/28/health/28real.html|title=The Claim: Never Swim After Eating |publisher=New York Times|date=2005-06-28|accessdate=2011-01-16}}; {{Cite web|url=http://www.snopes.com/oldwives/hourwait.asp|title=Hour Missed Brooks|publisher=Snopes|date=2005-01-03|accessdate=2011-01-16}}</ref>
*A person who is [[drowning]] does not always wave and call for help. In the final stages, raising the arms and vocalising are even usually impossible due to the [[instinctive drowning response]].<ref>{{Cite |last=Vittone|first=Mario|title=It Doesn't Look Like They're Drowning|work=On Scene: The Journal of U.S. Coast Guard Search and Rescue|url=http://www.uscg.mil/hq/cg5/cg534/On%20Scene/OSFall06.pdf |page=14}}</ref> The technical term for the situation where a "drowning" person is capable of waving and calling for help is "aquatic distress".

===Mathematics===
{{main|0.999...}}
*Contrary to a widespread perception, the [[real number]] [[0.999...]]—where the dot is followed by an infinite sequence of nines—is exactly equal to 1 by definition.<ref>{{Cite book|last=Eccles|first=Peter J. |title= An introduction to mathematical reasoning: numbers, sets, and functions|year= 1997|publisher= [[Cambridge University Press]]|page=167|url=http://books.google.com/books?id=ImCSX_gm40oC&pg=PA167#v=onepage&q&f=false|isbn=0521597188|quote=Intuition suggests that this means that the repeating decimal<math>0.\bar{9}</math> is also less than 1, and this is a common misconception.}}</ref> They are two different ways of writing the same real number.<ref>{{Cite book|last=Maor|first=Eli |year= 1991 |title= To infinity and beyond: a cultural history of the infinite|publisher=[[Princeton University Press]]|page=32| ISBN=9780691025117|url=http://books.google.com/books?id=lXjF7JnHQoIC&pg=PA32#v=onepage&q&f=false|quote=Many people find it hard to accept this simple fact, and one can often hear a heated discussion as to its validity.}}</ref> A 2009 study by Weller ''et al.''<ref>K Weller, I Arnon, and E. Dubinsky. Preservice Teachers' Understanding of the Relation Between a Fraction or Integer and Its Decimal Expansion. Canadian Journal of Science, Mathematics and Technology Education, 1942-4051, Volume 9 (2009), no. 1, 5--28.</ref> states that "[[David O. Tall|Tall]] and Schwarzenberger (1978) asked first year university mathematics students whether 0.999... is equal to 1. The majority of the students thought that 0.999... is less than 1." Weller ''et al'' go on to describe their own controlled experiment, performed "during the 2005 fall semester at a major research university in the southern United States. Pre-service elementary and middle school teachers from all five sections of a sophomore-level mathematics content course on number and operation participated in the study." The results are striking: "On the question of whether .999...=1, 72% of the control group and 83% of the experimental group expressed their view that .999... is not equal to 1."

===Physics===
*Contrary to the common myth,<ref>{{Cite web|url=http://www.ems.psu.edu/~fraser/Bad/BadCoriolis.html|first=Alistair |last=Frasier |title=Bad Coriolis |publisher=[[Penn State]] College of Earth an Materials Sciences|work=ems.psu.edu|date=October 16, 1996 |accessdate=2009-08-29}}</ref> the [[Water vortex|Coriolis effect]] does not determine the direction that water rotates in a bathtub drain or a flushing toilet. The Coriolis effect induced by the Earth's rotation becomes significant and noticeable only at large scales, such as in weather systems or oceanic currents.<ref>{{Cite web|url=http://www.snopes.com/science/coriolis.asp|title=Coriolis Force Effect on Drains|publisher=snopes.com|date=|accessdate=2010-06-23}}</ref> In addition, most toilets inject water into the bowl at an angle, causing a spin too fast to be significantly affected by the Coriolis effect.<ref>{{Cite web|title=Which way will my bathtub drain|url=http://math.ucr.edu/home/baez/physics/General/bathtub.html|publisher=Usenet Physics FAQ|accessdate=2008-08-07}}</ref>
*[[Gyroscope|Gyroscopic forces]] are not required for a rider to [[bicycle and motorcycle dynamics#Other hypotheses|balance]] a [[bicycle]].<ref name="whitt">{{Cite book|title=Bicycling Science|edition=Second|last=Whitt|first=Frank R.|first2=David G. |last2=Wilson|year=1982|publisher=Massachusetts Institute of Technology| isbn=0-262-23111-5| pages=198–233}}</ref><ref name="klein">{{Cite web|url=http://www.losethetrainingwheels.org/default.aspx?Lev=2&ID=34 |publisher=LoseTheTrainingWheels.org| archiveurl=http://web.archive.org/web/20061010070125/http://www.losethetrainingwheels.org/default.aspx?Lev=2&ID=34 |archivedate=2006-10-10|title=Bicycle Science|last=Klein|first=Richard E.|coauthors=et al.|accessdate=2006-08-04}}</ref><ref name="jones">{{Cite journal |last1=Jones |first1=David E. H. |pages=34–40 |title=The Stability of the Bicycle |volume=23 |journal=Physics Today |year=1970 |url=http://socrates.berkeley.edu/%7Efajans/Teaching/MoreBikeFiles/JonesBikeBW.pdf |doi=10.1063/1.3022064}}</ref><ref name="DCL">{{cite web|url=http://www.dclxvi.org/chunk/tech/trail/ |title=An Introduction to Bicycle Geometry and Handling |author=Megulon5 |publisher=DCLXVI.org |work=CHUNK666 |quote=negated the gyroscopic action of the front wheel by mounting another wheel on the same axle and spinning it in the opposite direction. He says that it felt strange, but was easily ridable. However, when set in motion without a rider, it collapsed much quicker than normal, and he found it difficult (although not impossible) to ride with his hands off of the handlebars.}}{{dubious|date=January 2011}}</ref> Although gyroscopic forces are a factor, the stability of a bicycle is determined primarily by inertia,<ref name="DCL"/> steering geometry, and the rider's ability to counteract tilting by steering. [[Image:Equal transit-time NASA wrong1.gif|thumb|right|250px|An illustration of the equal transit-time fallacy.]]
*It is not true that air takes the same time to travel above and below an aircraft's wing.<ref name=NASA_Incorrect_Theory1>{{Cite web|url=http://www.grc.nasa.gov/WWW/K-12/airplane/wrong1.html |title=Incorrect Lift Theory |publisher=NASA Glenn Research Center |work=grc.nasa.gov |date=July 28, 2008 |accessdate=2011-01-13}} (Java applet).</ref> This misconception, illustrated at right, is widespread among textbooks and non-technical reference books, and even appears in pilot training materials. In fact the air moving over the top of an airfoil generating lift is always moving much faster than the equal transit theory would imply,<ref name=NASA_Incorrect_Theory1/> as described in the [[Lift_(force)#.22Popular.22_explanation_based_on_equal_transit-time|incorrect]] and [[Lift_(force)#A_more_rigorous_physical_description|correct explanations]] of lift force.
*The idea that [[lightning]] never strikes the same place twice is one of the oldest and most well-known [[superstition]]s about lightning. There is no reason that lightning would not be able to strike the same place twice; if there is a thunderstorm in a given area, then objects and places which are more prominent or conductive (and therefore minimize distance) are more likely to be struck. For instance, lightning strikes the [[Empire State Building]] in [[New York City]] about 100 times per year.<ref>{{Cite web|url=http://www.sti.nasa.gov/tto/Spinoff2005/ps_3.html|title=spinoff 2005-Lightning Often Strikes Twice|publisher=Office of the Chief Technologist, [[NASA]]|work = Spinoff |date=March 25, 2010|accessdate=2010-06-23}}</ref><ref>{{Cite web|author=Staff |url=http://weather.weatherbug.com/weather-news/weather-reports.html?story=6571 |title=Full weather report story from WeatherBug.com |publisher=Weather.weatherbug.com|date=May 17, 2010|accessdate=2010-06-23}}</ref>
*Although frequently repeated as fact, a [[penny]] dropped from the [[Empire State Building]] will not kill a person or crack the sidewalk. Due to [[terminal velocity]] the speed of a falling penny cannot exceed 30–50 miles per hour regardless of the distance from which it is dropped,<ref>{{Cite web|url=http://www.misconceptionjunction.com/index.php/2010/10/dropping-a-penny-from-the-top-of-the-empire-state-building-isnt-dangerous/|title=Dropping A Penny From The Top Of The Empire State Building Isn't Dangerous|publisher=misconceptionjunction.com}}</ref> as demonstrated on an episode of [[MythBusters_(2003_season)#Penny_Drop|Mythbusters]].

===Psychology===
*The notion of [[catharsis]] holds that frustration and anger should not be bottled up or else a person risks allowing those feelings to accrue and eventually explode in some harmful way. Instead, it recommends that frustration and anger should be released through harmless expression, such as by screaming or punching a pillow. However, experimental psychology has shown that such expression can increase rather than decrease harmful behavior.<ref>{{Cite web|url=http://devoidarex.newsvine.com/_news/2006/02/28/112741-the-myth-of-catharsis-maybe-you-ought-to-leave-that-pillow-alone|title=The Myth of Catharsis: Maybe You Ought to Leave that Pillow Alone|publisher=newsvine.com}}</ref> In one experiment, people who engaged in catharsis (by hitting a punching bag) were significantly more likely to aggress toward a peer shortly afterward than were people who did not engage in catharsis.<ref>Bushman, B. J., Baumeister, R. F., & *Stack, A. D. (1999). Catharsis, aggression, and persuasive influence: Self-fulfilling or self-defeating prophecies? Journal of Personality and Social Psychology, 76, 367-376.</ref>
*Photographic or [[eidetic memory]] refers to the ability to remember images with extremely high precision – so high as to mimic a camera. However, it is highly unlikely that photographic memory exists, as to date there is no hard scientific evidence that anyone has ever had it.<ref>{{Cite web|url=http://indianapublicmedia.org/amomentofscience/photographic-memory/|title=Photographic Memory|publisher=indianapublicmedia.org}}</ref> Many people have claimed to have a photographic memory, but those people have been shown to have good memories as a result of [[mnemonic|mnemonic devices]] rather than a natural capacity for detailed memory encoding.<ref>{{Cite web|url=http://www.slate.com/id/2140685/|title=Kaavya Syndrome The accused Harvard plagiarist doesn't have a photographic memory. No one does.|publisher=slate.com}}</ref>

==Sports==
[[File:Marcos black belt.jpg|thumb|right|250px|[[Marcos Torregrosa]] wearing a black belt with a red bar. In some martial arts, such as [[Brazillian Jiu Jitsu]] and [[Judo]], red belts indicate a higher rank than black. In some cases, a solid red belt is reserved for the founder of the art, and in others, higher degrees of black belts are shown by red stripes.]]
*[[Abner Doubleday]] did not invent [[baseball]].<ref>{{Cite news|last=Cole|first=Diane|url=http://www.usnews.com/usnews/news/articles/060806/14ball.htm|title=Contrary to myth, baseball may have had no single inventor|publisher=US News and World Report|date=1990-10-04|accessdate=2009-08-06}}</ref><ref>{{Cite news|last=Fox|first=Butterfield|url=http://www.nytimes.com/1990/10/04/nyregion/cooperstown-hoboken-try-new-york-city.html|title=Cooperstown? Hoboken? Try New York City|publisher=The New York Times|date=1990-10-04|accessdate=2009-04-03}}</ref> {{See|Origins of baseball#The Abner Doubleday myth}}
*The [[World Series]] is not named after the ''[[New York World]]'' newspaper.<ref>{{Cite web|url=http://www.snopes.com/business/names/worldseries.asp|title=World Series|publisher=snopes.com|date=|accessdate=2010-06-23}}</ref>
*The [[black belt (martial arts)|black belt]] in [[martial arts]] does not necessarily indicate expert level or mastery. As introduced for [[judo]] in the 1880s, it indicates competency of all of the basic techniques of the sport. The first five [[Dan (rank)|ranks]] all have black belts; holders of the third rank can act as local instructors and may be addressed as ''[[sensei]]''. Holders of higher ranks in judo and other Asian martial arts are awarded belts with alternating red and white panels (6th to 8th ''dan''), and the very highest ranks with solid red belts (9th and 10th ''dan'').<ref>{{cite web|url=http://r25.jp/magazine/ranking_review/10002000/1112008051512.html|title=柔道帯の最高位は、何と紅!? “紅帯”所持者に投げられてきた!|language=Japanese|publisher=R25.jp|date=2008-05-15|accessdate=2008-11-11 |archiveurl = http://web.archive.org/web/20080519163156/http://r25.jp/magazine/ranking_review/10002000/1112008051512.html  |archivedate = 2008-05-19}}</ref>

==Religion==
===Book of Genesis===

*The [[forbidden fruit]] mentioned in the [[Book of Genesis]] is commonly assumed to be an apple,<ref>{{Cite book|title=Voices from the University: The Legacy of the Hebrew Bible|author=Szpek, Heidi|page=92|isbn=9780595256198}}</ref> and is widely depicted as such in Western art, although the Bible does not identify what type of fruit it is. The original Hebrew texts mention only ''tree'' and ''fruit''. Early Latin translations use the word ''mali'', which can be taken to mean both "evil" and "apple". German and French artists commonly depict the fruit as an apple from the 12th century onwards, and [[John Milton]]'s ''[[Areopagitica]]'' from 1644 explicitly mentions the fruit as an apple.<ref>{{Cite web|title=The Straight Dope: Was the forbidden fruit in the Garden of Eden an apple?|author=Cecil Adams|url=http://www.straightdope.com/columns/read/2682/was-the-forbidden-fruit-in-the-garden-of-eden-an-apple|accessdate=2010-01-15}}</ref> Jewish scholars suggested that the fruit could have been a grape, a fig, wheat, or [[etrog]].<ref>[[Babylonian Talmud]], [[Berakhot (Talmud)|Berakhot]], 40a</ref><ref>[[Genesis Rabba]] 15 7</ref><ref>[http://www.straightdope.com/columns/read/2682/was-the-forbidden-fruit-in-the-garden-of-eden-an-apple The Straight Dope: Was the forbidden fruit in the Garden of Eden an apple?]</ref> Likewise, the Quran speaks only of a forbidden "tree" and does not identify the fruit.
*Although common conception says that [[Noah]] was told in the [[Book of Genesis]] to bring two of each animal onto his ark,<ref name="ArkAnimals">{{cite web | url=http://listverse.com/2008/04/20/top-10-misconceptions-about-the-bible/ | title=Top 10 Misconceptions about the Bible | accessdate=2011-01-10 | date=2008-04-20 | publisher=Listverse.com}}</ref> the book actually contains differing passages about the number of animals he was told to bring; in {{Bibleverse||Genesis|6:19|NIV}}, he is told to bring "two of all living creatures", while in {{Bibleverse||Genesis|7:2|NIV}} he is told to bring "seven pairs of every kind of clean animal […] and one pair of every kind of unclean animal" - although in some translations (e.g. the New King James {{Bibleverse||Genesis||7:2|NKJV}}) this is rendered as seven animals, rather than seven pairs.

===Buddhism===
*The [[Gautama Buddha|historical Buddha]] was not obese. The "chubby Buddha" or "laughing Buddha" is a tenth century Chinese folk hero by the name of [[Budai]]. In Chinese Buddhist culture, Budai came to be revered as an [[incarnation]] of [[Maitreya]], the [[Bodhisattva]] who will become a Buddha to restore Buddhism after the teachings of the historical Buddha, Siddhārtha Gautama, have passed away.<ref>{{cite web|url=http://buddhism.about.com/od/buddha/a/laughingbuddha.htm|title=The Laughing Buddha|accessdate=January 6, 2011|source=about.com}}</ref>
*The Buddha is not a [[god]]. In early Buddhism, Siddhārtha Gautama possessed no salvific properties and strongly encouraged "self-reliance, self discipline and individual striving."<ref>{{cite web|url=http://www.buddhanet.net/e-learning/snapshot01.htm|title=Buddhism - Major Differences |accessdate=January 6, 2011|source=Buddhanet.net}}</ref> However, in later developments of [[Mahayana|Mahāyāna Buddhism]], notably in the [[Pure Land Buddhism|Pure Land (Jìngtǔ)]] school of Chinese Buddhism, the [[Amitābha|Amitābha Buddha]] was thought to be a [[Salvation|savior]]. Through faith in the Amitābha Buddha, one could be reborn in the [[Pure Land|western Pure Land]]. Although in Pure Land Buddhism the Buddha is considered a savior, he is still not considered a god in the common understanding of the term.<ref>{{cite web|url=http://www.buddhanet.net/e-learning/history/b3schchn.htm|title=The Chinese Buddhist Schools|accessdate=January 6, 2011|source=Buddhanet.net}}</ref>

===Christianity===
* Nowhere in the Bible is [[Satan]] described as ruling over or being in Hell. Throughout the Bible Satan is described as constantly on Earth, and the [[Book of Revelation]] says that after Judgment Satan will be cast into Hell.<ref>{{cite news |title=What Does the Bible Say About…Satan in Hell? |author=O'Hearn, Timothy James |url=http://www.minuteswithmessiah.com/question/sataninhell.html |newspaper=Minutes With Messiah |year=2005 |accessdate=January 16, 2011}}</ref>
*The [[Immaculate Conception]] is not synonymous with the [[virgin birth of Jesus]], nor is it a supposed belief in the virgin birth of [[Mary (mother of Jesus)|Mary]], his mother. Rather, the Immaculate Conception is the [[Roman Catholic]] belief that Mary was not subject to [[original sin]] from the first moment of her existence, when she was conceived.<ref>{{Cite web|title=Religion & Ethics - Beliefs: The Immaculate Conception|url=http://www.bbc.co.uk/religion/religions/christianity/beliefs/immaculateconception.shtml|year=2009|publisher=BBC.co.uk| accessdate=2011-01-05}}</ref> The concept of the virgin birth, on the other hand, is the belief that Mary miraculously conceived [[Jesus]] while remaining a virgin.<ref>''Erratum: The BBC article errs in its statement of the virgin birth it says "Mary gave birth to Jesus while remaining a virgin" which, as stated, is part of the doctrine of [[Perpetual virginity of Mary|Perpetual Virginity]]. The correct formulation is "that Mary miraculously conceived Jesus while remaining a virgin" as stated in [[virgin birth of Jesus|the Wikipedia article on the virgin birth of Jesus]]'' Retrieved 2011-01-05.</ref>
*Nowhere in the Bible does it say exactly three [[Biblical Magi|magi]] came to visit the baby Jesus, nor that they were kings, rode on camels, or that their names were Casper, Melchior and Balthazar. Matthew 2 has traditionally been combined with Isaiah 60:1-3.
60:1 Arise, shine, for your light has come,
and the glory of the Lord has risen upon you.
2 For behold, darkness shall cover the earth,
and thick darkness the peoples;
but the Lord will arise upon you,
and his glory will be seen upon you.
3 And nations shall come to your light,
and kings to the brightness of your rising.

Three magi are supposed because three gifts are described, and [[Nativity of Jesus in art|artistic depictions of the nativity]] after about the year 900 almost always depict three magi.<ref>{{Cite book|title=''Iconography of Christian Art, Vol. I'',1971 (English trans from German),|author=G. Schiller|isbn=0853312702|page=105}}</ref> Additionally, the wise men in the actual biblical narrative did not visit on the day Jesus was born, but they saw Jesus as a child, in a house as many as two years afterwards ({{bibleverse|Matthew||2:11}}).<ref>{{Cite web|last=Mikkelson|first=David and Barbara|title=Snopes.com - Three Wise Men|url=http://www.snopes.com/holidays/christmas/3wisemen.asp|accessdate=2009-04-07 }}</ref><ref>[[Geza Vermes]], ''The Nativity: History and Legend'', London, Penguin, 2006, p22</ref>
*Contrary to popular belief, there is no evidence that Jesus was born on December 25.<ref name=autogenerated1>{{Cite web|title=Why Jesus Christ Wasn't Born on December 25|url=http://www.gnmagazine.org/booklets/HH/jcnotborndec25.asp|publisher=United Church of God|work=gnmagazine.org|accessdate=2011-01-13}}</ref> The Bible never claims a date of December 25, but may imply a date closer to September.<ref name=autogenerated1 /> The date may have initially been chosen to correspond with either the day exactly nine months after Christians believe [[Annunciation|Jesus to have been conceived]],<ref name="bib-arch.org">{{cite web|url=http://www.bib-arch.org/e-features/christmas.asp |title=How December 25 Became Christmas|publisher=Biblical Archaeology Review|accessdate=2009-12-13}}</ref> the date of the [[Roman calendar|Roman]] [[winter solstice]],<ref name="Newton">Newton, Isaac, ''[http://www.gutenberg.org/files/16878/16878-h/16878-h.htm Observations on the Prophecies of Daniel, and the Apocalypse of St. John]'' (1733). Ch. XI. "''A sun connection is possible because Christians consider Jesus to be the "sun of righteousness" prophesied in Malachi 4:2.''"</ref> or one of various ancient [[List of winter festivals|winter festivals]].<ref name="bib-arch.org"/><ref name="SolInvictus">"{{cite book|last=Roll|first=Susan K.| title=Toward the Origins of Christmas| publisher=Peeters | year=1995| page=130| url=http://books.google.com/books?id=6MXPEMbpjoAC&lpg=PP1&ots=beccd692iI&pg=PA130#v=onepage&q&f=false}} Tighe, William J. (December 2003), "[http://touchstonemag.com/archives/article.php?id=16-10-012-v Calculating Christmas]". Touchstone Magazine. ([http://www.webcitation.org/5kwR1OTxS Archived 2009-10-31]).</ref>

===Islam===
*A [[fatwā]] is a non-binding legal opinion issued by an [[Ulema|Islamic scholar]] under [[Sharia|Islamic law]]. The popular misconception<ref>{{Cite journal|last=Isbister|first=William H. |title=A “good” fatwa|url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1124693/| journal=[[British Medical Journal]] |date=November 23, 2002|volume=325 |issue=7374 |page=1227 |pmcid=PMC1124693 |accessdate=2009-04-08 }}</ref><ref>{{Cite journal |last=Vultee |first=Fred|title=Fatwa on the Bunny|url=http://jci.sagepub.com/cgi/content/abstract/30/4/319?ck=nck |journal=Journal of Communication Inquiry |date=October 2006 |volume=30|issue=4|pages= 319–336 |doi=10.1177/0196859906290919 |accessdate=2009-12-19 }}</ref> that the word means a death sentence probably stems from the fatwā issued by Ayatollah [[Ruhollah Khomeini]] of Iran in 1989 regarding the author [[Salman Rushdie]], who he stated had earned a death sentence for [[blasphemy]]. This event led to fatwās gaining widespread media attention in the West.<ref>{{Cite news|title=In Depth: Islam, Fatwa FAQ|url=http://www.cbc.ca/news/background/islam/fatwa.html|publisher=CBC News Online | date=June 15, 2006|accessdate=2009-04-08 }}</ref>
*The word "[[jihad]]" does not always mean "[[Religious war|holy war]]"; literally, the word in Arabic means "struggle". While there is such a thing as "[[Jihad#Warfare_.28Jihad_bil_Saif.29|jihad bil saif]]", or jihad "by the sword",<ref>{{cite book|first=Majid |last=Khadduri |title=War and Peace in the Law of Islam |publisher=[[Johns Hopkins Press]] |year=1955 |pages=74–80 |url=http://books.google.com/books?id=UHWd6gLZsFIC&lpg=PP1&pg=PA74#v=onepage&q&f=false}}</ref> many modern Islamic scholars usually say that it implies an effort or struggle of a spiritual kind.<ref>{{cite book|first=Brandon |last=Toropov |first=Luke |last=Buckles|title=The Complete Idiot's Guide to World Religions, 3rd ed.|page=157 |publisher=Alpha|year=2004| isbn=978-1592572229| url=http://books.google.com/books?id=ZPokHByS3N0C&pg=PA157#v=onepage&q&f=false}}</ref><ref>{{cite news|url=http://www.kuna.net.kw/NewsAgenciesPublicSite/ArticleDetails.aspx?id=1719934&Language=en|title=Western definition of "jihad" must be corrected -- Italian expert |date=March 29, 2007|newspaper=[[Kuwait News Agency]] (KUNA)}}</ref> Scholar [[Louay Safi]] asserts that "misconceptions and misunderstandings regarding the nature of war and peace in Islam are widespread in both the Muslim societies and the West", as much following [[9/11]] as before.<ref>{{cite book| title=Peace and the Limits of War: Transcending the Classical Conception of Jihad |first=Louay M. |last=Safi |url=http://books.google.com/books?id=1_PFEicd5LkC&pg=PP9#v=onepage&q&f=false |publisher=[[International Institute of Islamic Thought]]| year=2003 |page=preface |isbn=1565644026}}</ref>

===Judaism===
*A person with a tattoo is not generally forbidden from being buried in a Jewish cemetery.<ref>{{cite web|url=http://www.nytimes.com/2008/07/17/fashion/17SKIN.html?_r=3&pagewanted=1&ref=fashion |title=Skin Deep - Hey, Mom, the Rabbi Approved My Tattoo |publisher=NYTimes.com|date=July 17, 2008|accessdate=2011-01-13}}</ref> This common misconception was depicted in the television shows ''[[Curb Your Enthusiasm]]'' and ''[[The Nanny]]''. While private cemeteries have the right to forbid burial on any grounds, there is no Jewish law to bar tattooed applicants,<ref>{{cite web|url=http://www.ou.org/index.php/jewish_action/print/69707/ |title=What's the Truth About a Jew with a Tattoo being buried in a Jewish Cemetery |publisher=OU.org|accessdate=2011-01-13}}</ref> and it is uncommon to do so.<ref>{{cite web|url=http://www.chabad.org/library/article_cdo/aid/533444/jewish/Can-a-person-with-a-tattoo-be-buried-in-a-Jewish-cemetery.htm |title=Can a person with a tattoo be buried in a Jewish cemetery? |publisher=Chabad.org|accessdate=2011-01-13}}</ref>
* Orthodox Jews do not have sex through a hole in a sheet, as portrayed in various films and TV programs such as ''[[Curb Your Enthusiasm]]'' and ''[[A Price Above Rubies]]''.<ref>{{cite web|url=http://www.snopes.com/religion/sheet.asp |title=Hole in Sheet Sex |publisher=Snopes.com|accessdate=January 6, 2011}}</ref> In fact, according to Rabbi [[Shmuley Boteach]], "Jewish law does not allow any articles of clothing to be worn during lovemaking", and using a sheet in this way could be considered a violation of that law.<ref name="orthodox_jews_sex">{{cite web|url=http://www.wnd.com/news/article.asp?ARTICLE_ID=38069 |title=Holy Sex and Holy Walls |publisher=WND.com|accessdate=January 6, 2011}}</ref> This also includes wearing a condom.<ref name="orthodox_jews_sex"/>

==Technology==
===Inventions===
*[[George Washington Carver]] did not invent [[peanut butter]], though he reputedly discovered three hundred uses for peanuts and hundreds more for soybeans, pecans, and sweet potatoes.<ref>[http://peanut-butter.org/peanut-butter/History+of+Peanut+Butter History of Peanut Butter] Peanut-butter.org.</ref><ref>[http://www.americanscientist.org/bookshelf/pub/a-true-renaissance-man A True Renaissance Man]. [[American Scientist]].</ref>
*[[Thomas Crapper]] did not invent the [[flush toilet]];<ref>{{Cite web|url=http://www.snopes.com/business/names/crapper.asp|title=Thomas Crapper|work=[[Snopes]]|date=2007-02-22|accessdate=2008-12-13}}</ref> it was invented by [[John Harington (writer)|Sir John Harrington]] in 1596. Crapper, however, did much to increase its popularity and came up with some related inventions, such as the [[ballcock]] mechanism used to fill toilet tanks. He was noted for the quality of his products and received several [[Royal Warrant]]s. He was not the origin of the word ''[[feces|crap]]'', but his name may have helped popularize it.
*[[Thomas Edison]] did not invent the [[light bulb]].<ref>{{Cite book|last=Robert|first=Friedel|coauthors=Paul Israel|title=Edison's Electric Light: Biography of an Invention|location=[[New Brunswick, New Jersey]]|publisher=Rutgers University Press|pages=115–117|year=1987|isbn=0813511186}}</ref> He did, however, develop the first practical light bulb in 1880 (employing a carbonized bamboo filament), shortly prior to [[Joseph Swan]], who invented an even more efficient bulb in 1881 (which used a cellulose filament).
*[[Eli Whitney, Jr.|Eli Whitney]] did not invent the idea of [[interchangeable parts]]. He did help to popularize the idea.<ref name="Hounshell1984">{{Hounshell1984}}, pp. 15–47.</ref>
*[[Henry Ford]] did not invent either the [[automobile]] or the [[assembly line]]. He did help to develop the assembly line substantially, sometimes through his own engineering but more often through sponsoring the work of his employees.<ref name="Hounshell1984" />{{Page needed|date=September 2010}}<ref name="Sorensen1956">{{Citation | last = Sorensen | first = Charles E.; with Williamson, Samuel T. | authorlink = Charles E. Sorensen | year = 1956 | title = My Forty Years with Ford | publisher = Norton | location = New York | id = {{LCCN|56||010854}} |[http://books.google.com/books?id=fv9WPvAXpGMC&pg=PA128#v=onepage&f=false |page=128}}. Various republications, including ISBN 9780814332795.</ref>
*[[Guglielmo Marconi]] did not invent radio, but only modernized it for public broadcasting and communication.<ref>{{cite web|first=B. Eric |last=Rhoads |url=http://www.qsl.net/n7jy/radiohst.html |title=Just Who Invented Radio And Which Was The First Station? |publisher=QSL.net|accessdate=2011-01-13}}</ref><ref>{{cite web|url=http://www.ccrane.com/library/who-invented-radio.aspx |title=Who Invented Radio?|publisher=CCrane.com |work=WorldRadio |date= May 2006 |accessdate=2011-01-13}}</ref><ref>{{cite web| url=http://mobiledevdesign.com/standards_regulations/radio_invented_radio/ |title=Who invented radio?|date=February 1, 2002|first=Don |last=Bishop|publisher=Penton Media, Inc.|work=Mobile Dev & Design |accessdate=2011-01-13}}</ref> No single person was responsible for the [[invention of radio]].
*[[Robert Fulton]] did not invent the steamboat. [[John Fitch (inventor)|John Fitch]], [[James Rumsey]], [[William Symington]], and [[Samuel Morey]] each operated steamboats prior to Fulton.<ref>{{cite web|title= Samuel Morey - Inventor Extraordinary| work=Historical Fact Publications |year=1961 |first= Alice |last=Doan Hodgson|location=Orford, NH| url=http://kinnexions.com/smlsource/samuel.htm |publisher=Kinnexions.com |accessdate=2011-01-13}}</ref>
*[[Philo Farnsworth]] did not invent the television. The first television transmission was made in 1925 by Scottish inventor [[John Logie Baird]]<ref>[http://www.nature.com/nature/journal/v115/n2892/pdf/115504a0.pdf "Current Topics and Events"], ''[[Nature (journal)|Nature]]'', vol. 115, April 4, 1925, p. 505–506, doi:10.1038/115504a0</ref> using an electromechanical system. Farnsworth did transmit the first live human images in 1928,<ref>{{cite web|url=http://db3-sql.staff.library.utah.edu/lucene/Manuscripts/null/Ms0648.xml/complete |title=The Philo T. and Elma G. Farnsworth Papers|publisher=Utah.edu|accessdate=2011-01-13}}</ref> and was pioneering in the development of all-electronic television.
* [[Al Gore]] never said that he "invented" the Internet; Gore actually said, "During my service in the United States Congress, I took the initiative in creating the Internet."<ref>{{Cite web|url=http://www.snopes.com/quotes/internet.asp|title=Al Gore on the invention of the internet|publisher=Snopes|date=|accessdate=2009-08-29}}</ref><ref>http://www.csmonitor.com/Environment/Bright-Green/2009/0309/al-gore-joins-call-for-new-eco-internet-domain</ref> Gore was the original drafter of the [[High Performance Computing and Communication Act of 1991]], which provided significant funding for supercomputing centers, and this in turn led to upgrades of a major part of the already existing, early 1990s Internet backbone, the [[NSFNet]], and development of [[NCSA Mosaic]], the [[web browser|browser]] that popularized the [[World Wide Web]]; see [[Al Gore and information technology]].

===Transportation===
*The United States [[Interstate Highway System]] was not designed with airplane landings in mind. A common urban legend states that one out of every five (or ten) miles of highway must be straight and flat to allow emergency (or military) airplane landings, but this is not the case.<ref>{{Cite web|url=http://www.snopes.com/autos/law/airstrip.asp|title=Landing of Hope and Glory|publisher=snopes.com|accessdate=2007-12-30}}</ref><ref>{{Cite web|url=http://www.fhwa.dot.gov/publications/publicroads/00mayjun/onemileinfive.cfm|title=ONE MILE IN FIVE: Debunking the Myth|last=Weingroff|first=Richard F.|date=May/June 2000|work=Federal Highway Administration|accessdate=2006-06-29}}</ref> However, several parts of the German and later the Swiss [[Autobahn]] system were indeed designed to be auxiliary military air strips, both during [[World War II]] and the [[Cold War]].<ref>{{Cite web|url=http://www.lostplaces.de/cms/content/view/113/33/|title=Autobahn-Flugplätze (NLP-Str)|publisher=lostplaces.de|accessdate=2008-12-16}}</ref> Additionally, the [[Swedish Air Force]] built landing strips into their highway system starting in the 1950s with some expansion continuing into the 1990s.<ref>{{Cite web|url=http://www.flygbas.se/bilder/973.pdf|title=Svenska militära flygbaser|publisher=Fortifikationsverket}}</ref> [[List of highway strips in Poland|Poland]] also contains highway strips for landing and takeoff, as do Finland, Singapore<ref>{{Cite web|url=http://www.channelnewsasia.com/stories/singaporelocalnews/view/393262/1/.html|title=Lim Chu Kang Road converted into alternate runway|publisher=Channel NewsAsia|accessdate=2011-01-09}}</ref> and Bulgaria.{{Citation needed|date=January 2011}} The [[Eyre Highway]], which crosses the [[Nullarbor Plain]] in Australia, has four allocated areas for [[Royal Flying Doctor Service of Australia|Flying Doctor]] aircraft to land.
*Toilet waste is never intentionally dumped overboard from an aircraft. All waste is collected in tanks which are emptied on the ground by special toilet waste vehicles. A vacuum is used to allow the toilet to be flushed with less water and because plumbing cannot rely on gravity alone in an aircraft in motion.<ref>{{Cite web|url=http://www.howstuffworks.com/question314.htm|title=How does the toilet in a commercial airliner work?|author=How Stuff works|accessdate=2008-06-27}}</ref><ref>{{cite news|url=http://blogs.wsj.com/middleseat/2008/11/19/on-world-toilet-day-let-us-praise-the-airline-lav/|last=Philips|first=Matt|title=On World Toilet Day, Let Us Praise the Airline Lav|work=The Middle Seat Terminal (Wall Street Journal)|accessdate=2009-04-02|date=2008-11-19}}</ref> The infamous [[blue ice (aircraft)|blue ice]] is caused by accidental leakages from the waste tank. Passenger trains, on the other hand, have historically [[Passenger train toilets|flushed onto the tracks]]; however, modern trains usually have retention tanks on board the train.

==See also==
{{col-begin}}
{{Col-2}}
*[[Common misunderstandings of genetics]]
*[[Conventional wisdom]]
*[[Counter-intuitive]]
*[[Drug urban legends]]
*[[Factoid]]
*[[Jan Harold Brunvand]]
*[[List of misquotations]]
*[[List of topics related to public relations and propaganda]]
{{Col-2}}
*[[Misnomer]]
*[[MythBusters]]
*[[Old wives' tale]]
*''[[Pseudodoxia Epidemica]]''
*[[Snopes.com]]
*[[The Straight Dope]]
*[[Tornado myths]]
*[[Urban legend]]
{{col-end}}

==References==
{{Reflist|2}}

==Further reading==
*{{Cite book|last=Diefendorf|first=David|title=Amazing… But False!: Hundreds of "Facts" You Thought Were True, But Aren't|publisher=Sterling|year=2007|isbn=9781402737916}}
*{{Cite book|last=Green|first=Joey|title=Contrary to Popular Belief: More than 250 False Facts Revealed|publisher=Broadway|year=2005|isbn=978-0767919920}}
*{{Cite book|last=Johnsen|first=Ferris|title=The Encyclopedia of Popular Misconceptions: The Ultimate Debunker's Guide to Widely Accepted Fallacies|publisher=Carol Publishing Group|year=1994|isbn=9780806515564}}
*{{Cite book|last=Kruszelnicki|first=Karl|coauthors=Adam Yazxhi|title=Great Mythconceptions: The Science Behind the Myths|publisher=Andrews McMeel Publishing|year=2006|isbn=9780740753640}}
*{{Cite book|last=Lloyd|first=John|coauthors=John Mitchinson|title=The Book of General Ignorance|publisher=Harmony Books|year=2006|isbn=9780307394910}}
*{{Cite book|last=Lloyd|first=John|coauthors=John Mitchinson|title=The Second Book Of General Ignorance|publisher=Faber and Faber|year=2010|isbn=9780571268655}}
*{{Cite book|title=Origins of the Specious: Myths and Misconceptions of the English Language|last1=O'Conner|first1=Patricia T.|last2=Kellerman|first2=Stewart|year=2009|publisher=Random House|location=New York|isbn=9781400066605}}
*{{Cite book|last=Tuleja|first=Tad|title=Fabulous Fallacies: More Than 300 Popular Beliefs That Are Not True|publisher=Galahad Books|year=1999|isbn=978-1578660650}}
*{{Cite book|last=Varasdi|first=J. Allen|title=Myth Information: More Than 590 Popular Misconceptions, Fallacies, and Misbeliefs Explained!|publisher=Ballantine Books|year=1996|isbn=978-0345410498}}



{{DEFAULTSORT:List Of Common Misconceptions}}
[[Category:Society-related lists|Misconceptions]]
[[Category:Science activism]]
[[Category:Error]]

[[ar:قائمة المعتقدات الخاطئة]]
[[de:Verbreiteter Irrtum]]
[[hi:प्रचलित गलत धारणाओं की सूची]]
[[it:Lista delle comuni miscredenze]]
[[he:תפיסה שגויה]]
[[pl:Lista powszechnych błędnych mniemań]]

List of chief executive officers

2010-07-15T19:47:35Z

PhineasG:

The following is a '''list of [[chief executive officer]]s''' (CEOs) by company.



{| class="wikitable sortable"
|-
! Company !! Executive !! Title !! Since !! Education !! class="unsortable"|Notes
|-
| [[Accenture]]
| [[William D. Green]]
| CEO and Chairman<ref>http://www.accenture.com/Global/About_Accenture/Company_Overview/Executive_Leadership/WilliamBillDGreen.htm</ref>
| 2004
| [[Babson College]]
|
|-
| [[ACE Limited]]
| [[Evan G. Greenberg]]
| CEO and president<ref>http://www.acelimited.com/AceLimitedRoot/About+ACE/Executive+Team/Evan+G.+Greenberg.htm</ref>
| 2004
| [[New York University]] (attended); [[College of Insurance]] (attended)
| Former COO of [[American International Group]].
|-
| [[Aditya Birla Group]]
| [[Kumar Birla]]
| Chairman<ref>http://www.adityabirla.com/the_group/km_birla_profile.htm</ref>
| 1995<ref>http://www.adityabirla.com/media/press_reports/bio_sketch.htm</ref>
|
| Part of the [[Birla family]] business house in [[India]].
|-
| [[Adobe Systems]]
| [[Shantanu Narayen]]
| President and CEO<ref>http://www.adobe.com/aboutadobe/pressroom/executivebios/shantanunarayen.html</ref>
| 2007
| [[Osmania University]], [[Bowling Green State University]], [[Haas School of Business]]
| Formerly with [[Apple Inc.]]
|-
| [[Aftermath Entertainment]]
| [[Dr. Dre]]
| Founder and CEO
| 1996
|
|
|-
| [[Alcatel-Lucent]]
| [[Ben Verwaayen]]
| CEO
| 2008
| [[Utrecht University]]
|
|-
| [[Alcoa]]
| [[Klaus Kleinfeld]]
| Chairman and CEO<ref>http://alcoa.com/global/en/investment/officers.asp</ref>
| 2008
|
| Formerly with [[Siemens AG]].
|-
| [[Altria Group]]
| [[Michael Szymanczyk]]
| Chairman and CEO<ref>http://www.altria.com/en/cms/About_Altria/Our_Management_Team/Mike_Szymanczyk/default.aspx</ref>
| 2008
|
|
|-
| [[Amazon.com]]
| [[Jeff Bezos]]
| Founder, President, CEO, and Chairman<ref>http://phx.corporate-ir.net/phoenix.zhtml?c=97664&p=irol-govBio&ID=69376</ref>
| 1994
| [[Princeton University]]
|
|-
| [[AMD]]
| [[Dirk Meyer]]
| President and CEO<ref>http://www.amd.com/us/aboutamd/corporate-information/executives/Pages/dirk-meyer.aspx</ref>
| 2008
| [[University of Illinois at Urbana-Champaign]], [[Boston University Graduate School of Management]]
| Led development of the [[Athlon]] processor before executive management.
|-
| [[American Express]]
| [[Kenneth Chenault]]
| Chairman and CEO
| 2001
| [[Bowdoin College]], [[Harvard Law School]]
| Third African-American CEO of a Fortune 500 company.
|-
| [[Amgen]]
| [[Kevin W. Sharer]]
| President and CEO
| 2000
|
|
|-
| [[AMR Corporation]]
| [[Gerard Arpey]]
| Chairman, Preseident, and CEO<ref>http://www.aa.com/i18n/amrcorp/corporateInformation/bios/arpey.jsp</ref>
| 2003
|
| Parent company for [[American Airlines]].
|-
| [[ANADIGICS,Inc]]
| [[Mario A. Rivas]]
| President and CEO
| 2009<ref>http://www.tradingmarkets.com/.site/news/Stock%20News/2127801/</ref>
|
|
|-
| [[Analog Devices]]
| [[Jerald G Fishman]]
| CEO and President
| 1996
|
|
|-
| [[Anheuser-Busch]]
| [[Dave Peacock (business)|Dave Peacock]]
| CEO
| 2008
|
| Replaced [[August Busch IV]] after sale to [[InBev]].
|-
| [[Anil Dhirubhai Ambani Group]]
| [[Anil Ambani]]
|
|
|
|
|-
| [[Antigenics Inc.]]
| [[Garo H. Armen]]
|
|
|
|
|-
| [[AOL Inc.]]
| [[Tim Armstrong (executive)|Tim Armstrong]]
|
|
|
|
|-
| [[Applebee's International, Inc.]]
| [[Julia Stewart (businesswoman)|Julia Stewart]]
|
|
|
|
|-
| [[Apple Inc.]]
| [[Steve Jobs]]
|
|
|
|
|-
| [[Arcelor Mittal]]
| [[Lakshmi Niwas Mittal]]
|
|
|
|
|-
| [[Archer Daniels Midland]]
| [[Patricia Woertz]]
|
|
|
|
|-
| [[AT&T]]
| [[Randall L. Stephenson]]
|
|
|
|
|-
| [[Austar]]
| [[John Porter]]
|
|
|
|
|-
| [[Bad Boy Records]]
| [[Sean "Diddy" Combs]]
|
|
|
|
|-
| [[BAE Systems|BAE Systems Plc]]
| [[Ian King (BAE Systems)|Ian King]]
|
|
|
|
|-
| [[Banco Bilbao Vizcaya Argentaria|Banco Bilbao Vizcaya Argentaria (BBVA)]]
| [[Francisco González]]
|
|
|
|
|-
| [[Bank of America]]
| [[Brian Moynihan]]
|
|
|
|
|-
| [[Barclays]]
| [[John Silvester Varley]]
|
|
|
|
|-
| [[Barclays Capital]]
| [[Robert Diamond]]
|
|
|
|
|-
| [[Bellsouth]]
| [[F. Duane Ackerman]]
|
|
|
|
|-
| [[Berkshire Hathaway]]
| [[Warren Buffett]]
|
|
|
|
|-
| [[Best Buy]]
| [[Brian J. Dunn]]
|
|
|
|
|-
| [[Bharti Airtel|Bharti Telecom]]
| [[Sunil Mittal|Sunil Bharti Mittal]]
|
|
|
|
|-
| [[Blackstone Group]]
| [[Stephen A. Schwarzman]]
|
|
|
|
|-
| [[Bloodline Records]]
| [[DMX (rapper)|DMX]]
|
|
|
|
|-
| [[BMW]]
| [[Norbert Reithofer]]
|
|
|
|
|-
| [[Boeing]]
| [[W. James McNerney, Jr.]]
|
|
|
|
|-
| [[Borland]]
| [[Tod Nielsen]]
|
|
|
|
|-
| [[Boston Consulting Group]]
| [[Hans-Paul Bürkner]]
|
|
|
|
|-
| [[BP]]
| [[Tony Hayward]]
|
|
|
|
|-
| [[British Airways]]
| [[Willie Walsh]]
|
|
|
|
|-
| [[Bruegger's]]
| [[James J. Greco]]
|
|
|
|
|-
| [[Burger King]]
| [[John Chidsey]]
|
|
|
|
|-
| [[Campbell Soup Company]]
| [[Douglas R. Conant]]
|
|
|
|
|-
| [[Canonical Ltd.]]
| [[Mark Shuttleworth]]
|
|
|
|
|-
| [[Capital One Financial]]
| [[Richard Fairbank]]
|
|
|
|
|-
| [[Caterpillar Inc.]]
| [[James W. Owens]]
|
|
|
|-
| [[Cavium Networks]]
| [[Syed B. Ali]]
|
|
|
|-
| [[CBS Corporation]]
| [[Leslie Moonves]]
|
|
|
|-
| [[Chrysler]]
| [[Sergio Marchionne]]
|
|
|
|-
| [[Cisco Systems]]
| [[John Chambers (CEO)|John Chambers]]
|
|
|
|-
| [[Citigroup]]
| [[Vikram Pandit]]
|
|
|
|-
| [[The Coca-Cola Company|Coca-Cola]]
| [[Muhtar Kent]]
|
|
|
|-
| [[Cognizant Technology Solutions]]
| [[Francisco D'Souza]]
|
|
|
|-
| [[Comcast Corporation]]
| [[Brian L. Roberts]]
|
|
|
|-
| [[Compuware Corporation]]
| [[Peter Karmanos, Jr.]]
|
|
|
|-
| [[ConAgra]]
| [[Gary Rodkin]]
|
|
|
|-
| [[Continental Airlines]]
| [[Jeff Smisek]]
|
|
|
|-
| [[Cameron (company)|Cameron]]
| [[Sheldon Erikson]]
|
|
|
|-
| [[Crown Worldwide Group]]
| [[James E. Thompson]]
|
|
|
|-
| [[CVS Caremark]]
| [[Thomas Ryan]]
|
|
|
|-
| [[Cypress Semiconductor]]
| [[TJ Rodgers]]
|
|
|
|-
| [[Daimler AG]]
| [[Dieter Zetsche]]
|
|
|
|-
| [[Def Jam]]
| [[L.A. Reid]]
|
|
|
|-
| [[Dell, Inc.|Dell Inc]]
| [[Michael Dell]]
|
|
|
|-
| [[Delta Air Lines]]
| [[Richard Anderson]]
|
|
|
|-
| [[Deutsche Bank]]
| [[Josef Ackermann]]
|
|
|
|-
| [[Deutsche Post World Net]]
| [[Frank Appel]]
|
|
|
|-
| [[Digg]]
| [[Kevin Rose]]
|
|
|
|-
| [[Dish Network Corporation]]
| [[Charlie Ergen]]
|
|
|
|-
| [[DLF Universal]]
| [[Kushal Pal Singh]]
|
|
|
|-
| [[Domino's Pizza]]
| [[David Brandon]]
|
|
|
|-
| [[DuPont]]
| [[Ellen J. Kullman]]
|
|
|
|-
| [[Dubai Holdings]]
| [[Mohammed Al Gergawi]]
|
|
|
|-
| [[Dunkin' Donuts]]
| [[Jon L. Luther]]
|
|
|
|-
| [[Eastman Kodak]]
| [[Antonio M. Perez]]
|
|
|
|-
| [[EADS]]
| [[Louis Gallois]]
|
|
|
|-
| [[eBay]]
| [[John Donahoe]]
|
|
|
|-
| [[Electronic Arts]]
| [[John Riccitiello]]
|
|
|
|-
| [[Environment Agency]]
| [[Barbara Young, Baroness Young of Old Scone|Barbara Young]]
|
|
|
|-
| [[Ericsson]]
| [[Carl-Henric Svanberg]]
|
|
|
|-
| [[Eurasia Group]]
| [[Ian Bremmer]]
|
|
|
|-
| [[Exxon Mobil]]
| [[Rex Tillerson]]
|
|
|
|-
| [[Facebook]]
| [[Mark Zuckerberg]]
|
|
|
|-
| [[FedEx]]
| [[Frederick W. Smith]]
|
|
|
|-
| [[Free Software Foundation]]
| [[Richard Stallman]]
|
|
|
|-
| [[Fiat S.p.A.]]
| [[Sergio Marchionne]]
|
|
|
|-
| [[Fidelity Investments]]
| [[Abigail Johnson]]
|
|
|
|-
| [[Ford Motor Company]]
| [[Alan Mulally]]
|
|
|
|-
| [[Fox Learning Systems]]
| [[Debra Fox]]
|
|
|
|-
| [[Foxconn Electronics Inc]]
| [[Terry Gou]]
|
|
|
|-
| [[Fisher Investments]]
| [[Kenneth L. Fisher]]
|
|
|
|-
| [[FUBU]]
| [[Daymond John]]
|
|
|
|-
| [[Full Surface]]
| [[Swizz Beatz]]
|
|
|
|-
| [[Formula One Management]]
| [[Bernie Ecclestone]]
|
|
|
|-
| [[Gas Powered Games]]
| [[Chris Taylor (game designer)|Chris Taylor]]
|
|
|
|-
| [[General Dynamics]]
| [[Nicholas Chabraja]]
|
|
|
|-
| [[General Electric]]
| [[Jeffrey R. Immelt]]
|
|
|
|-
| [[General Motors Corporation|General Motors]]
| [[Edward Whitacre, Jr.]]
|
|
|
|-
| [[GfK AG]]
| [[Klaus L. Wübbenhorst]]
|
|
|
|-
| [[GlaxoSmithKline]]
| [[Andrew Witty]]
|
|
|
|-
| [[Goldman Sachs]]
| [[Lloyd Blankfein]]
|
|
|
|-
| [[Google]]
| [[Eric E. Schmidt]]
|
|
|
|-
| [[GMA Network]]
| [[Felipe Gozon]]
|
|
|
|-
| [[Halliburton]]
| [[David J. Lesar]]
|
|
|
|-
| [[Harley Davidson]]
| [[James Ziemer]]
|
|
|
|-
| [[Harvard Pilgrim|Harvard Pilgrim Health Care]]
| [[Charles D. Baker, Jr.|Charlie Baker]]
|
|
|
|-
| [[HCL Technologies]]
| [[Vineet Nayar]]
|
|
|
|-
| [[Henderson Land Development|Henderson Land Development Co. Ltd.]]
| [[Lee Shau Kee]]
|
|
|
|-
| [[Hewlett-Packard]]
| [[Mark V. Hurd]]
|
|
|
|-
| [[Hindalco]]
| [[Kumar Mangalam Birla]]
|
|
|
|-
| [[Home Depot]]
| [[Frank Blake]]
|
|
|
|-
| [[Honeywell]]
| [[David M. Cote]]
|
|
|
|-
| [[HP Hood LLC]]
| [[John A. Kaneb]]
|
|
|
|-
| [[HSBC]]
| [[Michael Geoghegan]]
|
|
|
|-
| [[IBM]]
| [[Samuel J. Palmisano]]
|
|
|
|-
| [[IKEA]]
| [[Anders Dahlvig]]
|
|
|
|-
| [[Inchcape plc]]
| [[André Lacroix (businessman)|André Lacroix]]
|
|
|
|-
| [[Infosys|Infosys Technologies Limited]]
| [[Kris Gopalakrishnan]]
|
|
|
|-
| [[Intel]]
| [[Paul Otellini]]
| CEO
| 2005
|
| Also serves on the board of [[Google]].<ref>http://investor.google.com/corporate/board-of-directors.html</ref>
|-
| [[ITC Limited]]
| [[Y C Deveshwar]]
| Chief Executive and Chairman of the Board<ref>http://www.itcportal.com/sets/leadership_frameset.htm</ref>
| 1996
|
| Has been with the company since 1968.
|-
| [[J.Crew]]
| [[Millard Drexler]]
| CEO
| 2003
|
| Former CEO of [[The Gap]], also director at [[Apple]]
|-
| [[Jefferies & Company]]
| [[Richard B. Handler]]
| CEO and Chairman
| 2001
|
|
|-
| [[JP Morgan Chase]]
| [[James Dimon]]
| CEO and Chairman
| 2004
|
| also on the board of the [[New York Federal Reserve]]
|-
| [[Juniper Networks]]
| [[Kevin Johnson (executive)|Kevin Johnson]]
| CEO
| 2008
|
| formerly of [[Microsoft]]
|-
| [[Kaplan, Inc.]]
| [[Andrew Rosen]]
|
|
|
|-
| [[Kingdom Holding Company]]
| [[Al-Waleed bin Talal]]
|
|
|
|-
| [[Koch Industries Inc.]]
| [[Charles G. Koch]]
|
|
|
|-
| [[Las Vegas Sands]]
| [[Sheldon Adelson]]
|
|
|
|-
| [[Lehman Brothers]]
| [[Richard S. (Dick) Fuld, Jr.]]
|
|
|
|-
| [[L.L. Bean]]
| [[Christopher McCormick]]
|
|
|
|-
| [[Larsen & Toubro Limited]]
| [[A M Naik]]
|
|
|
|-
| [[Lockheed Martin]]
| [[Robert Stevens]]
|
|
|
|-
| [[LPK]]
| [[Jerry Kathman]]
|
|
|
|-
| [[Macy's, Inc.]]
| [[Terry J. Lundgren]]
|
|
|
|-
| [[Manchester United F.C.|Manchester United]]
| [[David Gill (executive)|David Gill]]
|
|
|
|-
| [[Marks and Spencer]]
| [[Stuart Rose]]
|
|
|
|-
| [[McDonald's]]
| [[Jack Greenberg (McDonald's)|Jack Greenberg]]
|
|
|
|-
| [[McKinsey]]
| [[Ian Davis]]
|
|
|
|-
| [[Mercedes-Benz]]
| [[Dieter Zetsche]]
|
|
|
|-
| [[Merrill Lynch]]
| [[John Thain]]
|
|
|
|-
| [[Mesa Air Group]]
| [[Jonathan Ornstein]]
|
|
|
|-
| [[MetLife]]
| [[C. Robert Henrikson]]
|
|
|
|-
| [[MGA Entertainment]]
| [[Isaac Larian]]
|
|
|
|-
| [[Microsoft]]
| [[Steve Ballmer|Steven Anthony Ballmer]]
|
|
|
|-
| [[Mile High Comics]]
| [[Chuck Rozanski]]
|
|
|
|-
| [[Morgan Stanley]]
| [[John J. Mack]]
|
|
|
|-
| [[Motorola]]
| [[Greg Brown (businessman)|Greg Brown]]
|
|
|
|-
| [[Mozilla]]
| [[Mitchell Baker]]
|
|
|
|-
| [[MySQL AB]]
| [[Marten Mickos]]
|
|
|
|-
| [[MySpace]]
| [[Chris DeWolfe]]
|
|
|
|-
| [[National Amusements]]
| [[Sumner Redstone]]
|
|
|
|-
| [[NBC Universal, Inc.]]
| [[Jeff Zucker]]
|
|
|
|-
| [[Newlog]]
| [[Yochanan Vollach]]
|
|
|
|-
| [[News Corporation]]
| [[Rupert Murdoch|Keith Rupert Murdoch]]
|
|
|
|-
| [[New York Times Company]]
| [[Janet L. Robinson]]
|
|
|
|-
| [[NIIT]]
| [[Vijay K. Thadani]]
|
|
|
|-
| [[Nike, Inc.|Nike]]
| [[Mark Parker]]
|
|
|
|-
| [[Nissan]]
| [[Carlos Ghosn]]
|
|
|
|-
| [[Nokia]]
| [[Olli-Pekka Kallasvuo]]
|
|
|
|-
| [[Nortel]]
| [[Mike S. Zafirovski]]
|
|
|
|-
| [[Novartis]]
| [[Daniel Vasella]]
|
|
|
|-
| [[Nintendo]]
| [[Satoru Iwata]]
|
|
|
|-
| [[Office Depot]]
| [[Steve Odland]]
|
|
|
|-
| [[Oxford Sustainable Group]]
| [[Hadley Barrett]]
|
|
|
|-
| [[Oracle Corporation]]
| [[Larry Ellison]]
|
|
|
|-
| [[Orascom Telecom|Orascom Telecom Holding]]
| [[Naguib Sawiris]]
|
|
|
|-
| [[Outback Steakhouse]]
| [[Chris T. Sullivan]]
|
|
|
|-
| [[Patni Computer Systems]]
| [[Narendra Patni]]
|
|
|
|-
| [[PepsiCo]]
| [[Indra Nooyi]]
|
|
|
|-
| [[Perot Systems]]
| [[Peter Altabef]]
|
|
|
|-
| [[Pfizer]]
| [[Henry McKinnell]]
|
|
|
|-
| [[Pixar]]
| [[Steve Jobs]]
|
|
|
|-
| [[Pizza Hut]]
| [[David C. Novak]]
|
|
|
|-
| [[Playboy Enterprises]]
| [[Christie Hefner]]
|
|
|
|-
| [[Polo Ralph Lauren]]
| [[Ralph Lauren]]
|
|
|
|-
| [[Popular, Inc.]]
| [[Richard Carrión]]
|
|
|
|-
| [[Procter & Gamble]]
| [[Alan Lafley]]
|
|
|
|-
| [[Prudential Financial, Inc.]]
| [[John Strangfeld]]
|
|
|
|-
| [[Qantas|Qantas Airways Limited]]
| [[Alan Joyce (executive)|Alan Joyce]]
|
|
|
|-
| [[Qwest|Qwest Communications International]]
| [[Richard Notebaert]]
|
|
|
|-
| [[Reliance Industries Limited]]
| [[Mukesh Ambani]]
|
|
|
|-
| [[Renault]]
| [[Carlos Ghosn]]
|
|
|
|-
| [[Rite Aid Corporation]]
| [[Mary Sammons]]
|
|
|
|-
| [[Rocawear]]
| [[Jay-Z]]
|
|
|
|-
| [[Royal Ahold N.V.]]
| [[John Rishton]]
|
|
|
|-
| [[Royal Bank of Canada]]
| [[Gordon Nixon]]
|
|
|
|-
| [[Royal Bank of Scotland]]
| [[Stephen Hester]]
|
|
|
|-
| [[Royal Dutch Shell]]
| [[Peter Voser]]
|
|
|
|-
| [[Ryanair]]
| [[Michael O'Leary (Ryanair)|Michael O'Leary]]
|
|
|
|-
| [[S. C. Johnson & Son]]
| [[Herbert Fisk Johnson III]]
|
|
|
|-
| [[Saab Automobile|SAAB Automobile AB]]
| [[Jan-Åke Jonsson]]
|
|
|
|-
| [[Samsung]]
| [[Kun-Hee Lee]]
|
|
|
|-
| [[SAP AG]]
| [[Henning Kagermann]]
|
|
|
|-
| [[SAS Institute]]
| [[James Goodnight]]
|
|
|
|-
| [[Scottrade]]
| [[Rodger O. Riney]]
|
|
|
|-
| [[Seagate Technology]]
| [[Steve Luczo]]
|
|
|
|-
| [[Simon Property Group]]
| [[David Simon (CEO)|David Simon]]
|
|
|
|-
| [[Singapore Airlines]]
| [[Chew Choon Seng]]
|
|
|
|-
| [[SingTel]]
| [[Chua Sock Koong]]
|
|
|
|-
| [[Sirius Satellite Radio]]
| [[Mel Karmazin]]
|
|
|
|-
| [[Sleep Country Canada]]
| [[Steven Gunn]]
|
|
|
|-
| [[SoftBank]]
| [[Masayoshi Son]]
|
|
|
|-
| [[Southwest Airlines]]
| [[Gary C. Kelly]]
|
|
|
|-
| [[Sonic Drive-In]]
| [[J. Clifford Hudson]]
|
|
|
|-
| [[Sony]]
| [[Howard Stringer]]
|
|
|
|-
| [[Sony Computer Entertainment]]
| [[Kazuo Hirai]]
|
|
|
|-
| [[Starbucks Coffee Company]]
| [[Howard Schultz]]
|
|
|
|-
| [[Statoil]]
| [[Helge Lund]]
|
|
|
|-
| [[Sun Hung Kai|Sun Hung Kai Properties Ltd.]]
| [[Walter Kwok]]
|
|
|
|-
| [[Sun Microsystems]]
| [[Jonathan I. Schwartz]]
|
|
|
|-
| [[SunTrust Banks Inc.]]
| [[James M. Wells, III]]
|
|
|
|-
| [[Supervalu Inc.]]
| [[Jeff Noddle]]
|
|
|
|-
| [[Sulekha]]
| [[Satya Prabhakar]]
|
|
|
|-
| [[Swedbank]]
| [[Jan Lidén]]
|
|
|
|-
| [[Syntel Inc.]]
| [[Bharat Desai]]
|
|
|
|-
| [[Tata Consultancy Services]]
| [[N Chandrasekaran]]
|
|
|
|-
| [[Tata Steel]]
| [[B Muthuraman]]
|
|
|
|-
| [[Telmex]]
| [[Carlos Slim Helú]]
|
|
|
|-
| [[Telstra]]
| [[David Thodey]]
|
|
|
|-
| [[Temasek Holdings]]
| [[Ho Ching]]
|
|
|
|-
| [[Tesco PLC]]
| [[Terry Leahy|Sir Terry Leahy]] (retiring March 2011)
|
|
|
|-
| [[Thomson Reuters]]
| [[Tom Glocer]]
|
|
|
|-
| [[Tim Hortons]]
| [[Paul D. House]]
|
|
|
|-
| [[Time Warner]]
| [[Jeffrey L. Bewkes]]
|
|
|
|-
| [[TJX Companies, Inc.]]
| [[Carol Meyrowitz]]
|
|
|
|-
| [[Tracinda|Tracinda Corporation]]
| [[Kirk Kerkorian|Kerkor "Kirk" Kerkorian]]
|
|
|
|-
| [[The Siegel Group|The Siegel Group Nevada, Inc]]
| [[Steve Siegel|Stephen Siegel]]
|
|
|
|-
| [[The Travelers Companies]]
| [[Jay S. Fishman]]
|
|
|
|-
| [[Trump Organization]]
| [[Donald Trump]]
|
|
|
|-
| [[Toyota]]
| [[Hiroshi Okuda]]
|
|
|
|-
| [[Toys for Bob]]
| [[Paul Reiche III]]
|
|
|
|-
| [[Toys "R" Us]]
| [[Gerald L. Storch]]
|
|
|
|-
| [[Tradeking]]
| [[Donato A. Montanaro]]
|
|
|
|-
| [[Turner Broadcasting System, Inc.]]
| [[Philip I. Kent]]
|
|
|
|-
| [[Twitter]]
| [[Jack Dorsey]]
|
|
|
|-
| [[Tyson Foods, Inc.]]
| [[Richard L. Bond]] (former)
|
|
|
|-
| [[UAL Corporation]]
| [[Glenn F. Tilton]]
|
|
|
|-
| [[UBS AG]]
| [[Oswald Grübel]]
|
|
|
|-
| [[U.S. Century Bank]]
| [[Octavio Hernández]]
|
|
|
|-
| [[US Airways]]
| [[Doug Parker (airline executive)|Doug Parker]]
|
|
|
|-
| [[United Parcel Service]]
| [[D. Scott Davis]]
|
|
|
|-
| [[US Bancorp]]
| [[Richard K. Davis]]
|
|
|
|-
| [[UGI Corp.]]
| [[Lon R. Greenberg]]
|
|
|
|-
| [[United States Steel Corp.]]
| [[John P. Surma]]
|
|
|
|-
| [[United Technologies]]
| [[Louis R. Chênevert]]
|
|
|
|-
| [[Valero Energy Corporation]]
| [[William R. Klesse]]
|
|
|
|-
| [[Verizon]]
| [[Ivan Seidenberg]]
|
|
|
|-
| [[Viacom]]
| [[Philippe Dauman|Philippe P. Dauman]]
|
|
|
|-
| [[Viking Range]]
| [[Fred Carl, Jr.]]
|
|
|
|-
| [[Vodafone]]
| [[Vittorio Colao]]
|
|
|
|-
| [[Volkswagen]]
| [[Martin Winterkorn]]
|
|
|
|-
| [[Vulcan Inc.]]
| [[Paul Allen]]
|
|
|
|-
| [[The Walt Disney Company|Walt Disney Company, The]]
| [[Robert Iger]]
|
|
|
|-
| [[Walgreen Company]]
| [[Gregory Wasson]]
|
|
|
|-
| [[Wal-Mart]]
| [[Mike Duke]]
|
|
|
|-
| [[Warner Bros.]]
| [[Barry Meyer]]
|
|
|
|-
| [[Washington Mutual]]
| [[Kerry Killinger]]
|
|
|
|-
| [[The Washington Post Company]]
| [[Donald Graham]]
|
|
|
|-
| [[Whole Foods Market]]
| [[John Mackey (businessman)|John Mackey]]
|
|
|
|-
| [[Wikia, Inc.]]
| [[Gil Penchina]]
|
|
|
|-
| [[Windstream Corporation]]
| [[Jeffery Gardner]]
|
|
|
|-
| [[Winn-Dixie Stores]]
| [[Peter Lynch]]
|
|
|
|-
| [[Wipro Technologies]]
| [[Girish Paranjpe]] and [[Suresh Vaswani]]
|
|
|
|-
| [[World Wrestling Entertainment]]
| [[Vince McMahon]]
|
|
|
|-
| [[Yahoo!]]
| [[Carol Bartz]]
|
|
|
|-
| [[YG Entertainment]]
| [[Yang Hyun Suk]]
|
|
|
|-
| [[Young Money Entertainment]]
| [[Lil Wayne]]
|
|
|
|-
| [[YouTube, LLC]]
| [[Chad Hurley]]
|
|
|
|-
| [[Yum! Brands, Inc.]]
| [[David C. Novak]]
|
|
|
|}

== References ==
{{reflist}}

[[Category:Lists of businesspeople|CEO]]

[[ca:Llista d'executius en cap]]

List of chief executive officers

2010-07-15T19:44:18Z

PhineasG: began adding education column; all info directly from linked wp pages

The following is a '''list of [[chief executive officer]]s''' (CEOs) by company.



{| class="wikitable sortable"
|-
! Company !! Executive !! Title !! Since !! Education !! class="unsortable"|Notes
|-
| [[Accenture]]
| [[William D. Green]]
| CEO and Chairman<ref>http://www.accenture.com/Global/About_Accenture/Company_Overview/Executive_Leadership/WilliamBillDGreen.htm</ref>
| 2004
| [[Babson College]]
|
|-
| [[ACE Limited]]
| [[Evan G. Greenberg]]
| CEO and president<ref>http://www.acelimited.com/AceLimitedRoot/About+ACE/Executive+Team/Evan+G.+Greenberg.htm</ref>
| 2004
| [[New York University]] (attended); [[College of Insurance]] (attended)
| Former COO of [[American International Group]].
|-
| [[Aditya Birla Group]]
| [[Kumar Birla]]
| Chairman<ref>http://www.adityabirla.com/the_group/km_birla_profile.htm</ref>
| 1995<ref>http://www.adityabirla.com/media/press_reports/bio_sketch.htm</ref>
|
| Part of the [[Birla family]] business house in [[India]].
|-
| [[Adobe Systems]]
| [[Shantanu Narayen]]
| President and CEO<ref>http://www.adobe.com/aboutadobe/pressroom/executivebios/shantanunarayen.html</ref>
| 2007
| [[Osmania University]], [[Bowling Green State University]], [[Haas School of Business]]
| Formerly with [[Apple Inc.]]
|-
| [[Aftermath Entertainment]]
| [[Dr. Dre]]
| Founder and CEO
| 1996
|
|-
| [[Alcatel-Lucent]]
| [[Ben Verwaayen]]
| CEO
| 2008
| [[Utrecht University]]
|
|-
| [[Alcoa]]
| [[Klaus Kleinfeld]]
| Chairman and CEO<ref>http://alcoa.com/global/en/investment/officers.asp</ref>
| 2008
|
| Formerly with [[Siemens AG]].
|-
| [[Altria Group]]
| [[Michael Szymanczyk]]
| Chairman and CEO<ref>http://www.altria.com/en/cms/About_Altria/Our_Management_Team/Mike_Szymanczyk/default.aspx</ref>
| 2008
|
|-
| [[Amazon.com]]
| [[Jeff Bezos]]
| Founder, President, CEO, and Chairman<ref>http://phx.corporate-ir.net/phoenix.zhtml?c=97664&p=irol-govBio&ID=69376</ref>
| 1994
| [[Princeton University]]
|
|-
| [[AMD]]
| [[Dirk Meyer]]
| President and CEO<ref>http://www.amd.com/us/aboutamd/corporate-information/executives/Pages/dirk-meyer.aspx</ref>
| 2008
| [[University of Illinois at Urbana-Champaign]], [[Boston University Graduate School of Management]]
| Led development of the [[Athlon]] processor before executive management.
|-
| [[American Express]]
| [[Kenneth Chenault]]
| Chairman and CEO
| 2001
| [[Bowdoin College]], [[Harvard Law School]]
| Third African-American CEO of a Fortune 500 company.
|-
| [[Amgen]]
| [[Kevin W. Sharer]]
| President and CEO
| 2000
|
|-
| [[AMR Corporation]]
| [[Gerard Arpey]]
| Chairman, Preseident, and CEO<ref>http://www.aa.com/i18n/amrcorp/corporateInformation/bios/arpey.jsp</ref>
| 2003
| Parent company for [[American Airlines]].
|-
| [[ANADIGICS,Inc]]
| [[Mario A. Rivas]]
| President and CEO
| 2009<ref>http://www.tradingmarkets.com/.site/news/Stock%20News/2127801/</ref>
|
|-
| [[Analog Devices]]
| [[Jerald G Fishman]]
| CEO and President
| 1996
|
|-
| [[Anheuser-Busch]]
| [[Dave Peacock (business)|Dave Peacock]]
| CEO
| 2008
| Replaced [[August Busch IV]] after sale to [[InBev]].
|-
| [[Anil Dhirubhai Ambani Group]]
| [[Anil Ambani]]
|
|
|
|-
| [[Antigenics Inc.]]
| [[Garo H. Armen]]
|
|
|
|-
| [[AOL Inc.]]
| [[Tim Armstrong (executive)|Tim Armstrong]]
|
|
|
|-
| [[Applebee's International, Inc.]]
| [[Julia Stewart (businesswoman)|Julia Stewart]]
|
|
|
|-
| [[Apple Inc.]]
| [[Steve Jobs]]
|
|
|
|-
| [[Arcelor Mittal]]
| [[Lakshmi Niwas Mittal]]
|
|
|
|-
| [[Archer Daniels Midland]]
| [[Patricia Woertz]]
|
|
|
|-
| [[AT&T]]
| [[Randall L. Stephenson]]
|
|
|
|-
| [[Austar]]
| [[John Porter]]
|
|
|
|-
| [[Bad Boy Records]]
| [[Sean "Diddy" Combs]]
|
|
|
|-
| [[BAE Systems|BAE Systems Plc]]
| [[Ian King (BAE Systems)|Ian King]]
|
|
|
|-
| [[Banco Bilbao Vizcaya Argentaria|Banco Bilbao Vizcaya Argentaria (BBVA)]]
| [[Francisco González]]
|
|
|
|-
| [[Bank of America]]
| [[Brian Moynihan]]
|
|
|
|-
| [[Barclays]]
| [[John Silvester Varley]]
|
|
|
|-
| [[Barclays Capital]]
| [[Robert Diamond]]
|
|
|
|-
| [[Bellsouth]]
| [[F. Duane Ackerman]]
|
|
|
|-
| [[Berkshire Hathaway]]
| [[Warren Buffett]]
|
|
|
|-
| [[Best Buy]]
| [[Brian J. Dunn]]
|
|
|
|-
| [[Bharti Airtel|Bharti Telecom]]
| [[Sunil Mittal|Sunil Bharti Mittal]]
|
|
|
|-
| [[Blackstone Group]]
| [[Stephen A. Schwarzman]]
|
|
|
|-
| [[Bloodline Records]]
| [[DMX (rapper)|DMX]]
|
|
|
|-
| [[BMW]]
| [[Norbert Reithofer]]
|
|
|
|-
| [[Boeing]]
| [[W. James McNerney, Jr.]]
|
|
|
|-
| [[Borland]]
| [[Tod Nielsen]]
|
|
|
|-
| [[Boston Consulting Group]]
| [[Hans-Paul Bürkner]]
|
|
|
|-
| [[BP]]
| [[Tony Hayward]]
|
|
|
|-
| [[British Airways]]
| [[Willie Walsh]]
|
|
|
|-
| [[Bruegger's]]
| [[James J. Greco]]
|
|
|
|-
| [[Burger King]]
| [[John Chidsey]]
|
|
|
|-
| [[Campbell Soup Company]]
| [[Douglas R. Conant]]
|
|
|
|-
| [[Canonical Ltd.]]
| [[Mark Shuttleworth]]
|
|
|
|-
| [[Capital One Financial]]
| [[Richard Fairbank]]
|
|
|
|-
| [[Caterpillar Inc.]]
| [[James W. Owens]]
|
|
|
|-
| [[Cavium Networks]]
| [[Syed B. Ali]]
|
|
|
|-
| [[CBS Corporation]]
| [[Leslie Moonves]]
|
|
|
|-
| [[Chrysler]]
| [[Sergio Marchionne]]
|
|
|
|-
| [[Cisco Systems]]
| [[John Chambers (CEO)|John Chambers]]
|
|
|
|-
| [[Citigroup]]
| [[Vikram Pandit]]
|
|
|
|-
| [[The Coca-Cola Company|Coca-Cola]]
| [[Muhtar Kent]]
|
|
|
|-
| [[Cognizant Technology Solutions]]
| [[Francisco D'Souza]]
|
|
|
|-
| [[Comcast Corporation]]
| [[Brian L. Roberts]]
|
|
|
|-
| [[Compuware Corporation]]
| [[Peter Karmanos, Jr.]]
|
|
|
|-
| [[ConAgra]]
| [[Gary Rodkin]]
|
|
|
|-
| [[Continental Airlines]]
| [[Jeff Smisek]]
|
|
|
|-
| [[Cameron (company)|Cameron]]
| [[Sheldon Erikson]]
|
|
|
|-
| [[Crown Worldwide Group]]
| [[James E. Thompson]]
|
|
|
|-
| [[CVS Caremark]]
| [[Thomas Ryan]]
|
|
|
|-
| [[Cypress Semiconductor]]
| [[TJ Rodgers]]
|
|
|
|-
| [[Daimler AG]]
| [[Dieter Zetsche]]
|
|
|
|-
| [[Def Jam]]
| [[L.A. Reid]]
|
|
|
|-
| [[Dell, Inc.|Dell Inc]]
| [[Michael Dell]]
|
|
|
|-
| [[Delta Air Lines]]
| [[Richard Anderson]]
|
|
|
|-
| [[Deutsche Bank]]
| [[Josef Ackermann]]
|
|
|
|-
| [[Deutsche Post World Net]]
| [[Frank Appel]]
|
|
|
|-
| [[Digg]]
| [[Kevin Rose]]
|
|
|
|-
| [[Dish Network Corporation]]
| [[Charlie Ergen]]
|
|
|
|-
| [[DLF Universal]]
| [[Kushal Pal Singh]]
|
|
|
|-
| [[Domino's Pizza]]
| [[David Brandon]]
|
|
|
|-
| [[DuPont]]
| [[Ellen J. Kullman]]
|
|
|
|-
| [[Dubai Holdings]]
| [[Mohammed Al Gergawi]]
|
|
|
|-
| [[Dunkin' Donuts]]
| [[Jon L. Luther]]
|
|
|
|-
| [[Eastman Kodak]]
| [[Antonio M. Perez]]
|
|
|
|-
| [[EADS]]
| [[Louis Gallois]]
|
|
|
|-
| [[eBay]]
| [[John Donahoe]]
|
|
|
|-
| [[Electronic Arts]]
| [[John Riccitiello]]
|
|
|
|-
| [[Environment Agency]]
| [[Barbara Young, Baroness Young of Old Scone|Barbara Young]]
|
|
|
|-
| [[Ericsson]]
| [[Carl-Henric Svanberg]]
|
|
|
|-
| [[Eurasia Group]]
| [[Ian Bremmer]]
|
|
|
|-
| [[Exxon Mobil]]
| [[Rex Tillerson]]
|
|
|
|-
| [[Facebook]]
| [[Mark Zuckerberg]]
|
|
|
|-
| [[FedEx]]
| [[Frederick W. Smith]]
|
|
|
|-
| [[Free Software Foundation]]
| [[Richard Stallman]]
|
|
|
|-
| [[Fiat S.p.A.]]
| [[Sergio Marchionne]]
|
|
|
|-
| [[Fidelity Investments]]
| [[Abigail Johnson]]
|
|
|
|-
| [[Ford Motor Company]]
| [[Alan Mulally]]
|
|
|
|-
| [[Fox Learning Systems]]
| [[Debra Fox]]
|
|
|
|-
| [[Foxconn Electronics Inc]]
| [[Terry Gou]]
|
|
|
|-
| [[Fisher Investments]]
| [[Kenneth L. Fisher]]
|
|
|
|-
| [[FUBU]]
| [[Daymond John]]
|
|
|
|-
| [[Full Surface]]
| [[Swizz Beatz]]
|
|
|
|-
| [[Formula One Management]]
| [[Bernie Ecclestone]]
|
|
|
|-
| [[Gas Powered Games]]
| [[Chris Taylor (game designer)|Chris Taylor]]
|
|
|
|-
| [[General Dynamics]]
| [[Nicholas Chabraja]]
|
|
|
|-
| [[General Electric]]
| [[Jeffrey R. Immelt]]
|
|
|
|-
| [[General Motors Corporation|General Motors]]
| [[Edward Whitacre, Jr.]]
|
|
|
|-
| [[GfK AG]]
| [[Klaus L. Wübbenhorst]]
|
|
|
|-
| [[GlaxoSmithKline]]
| [[Andrew Witty]]
|
|
|
|-
| [[Goldman Sachs]]
| [[Lloyd Blankfein]]
|
|
|
|-
| [[Google]]
| [[Eric E. Schmidt]]
|
|
|
|-
| [[GMA Network]]
| [[Felipe Gozon]]
|
|
|
|-
| [[Halliburton]]
| [[David J. Lesar]]
|
|
|
|-
| [[Harley Davidson]]
| [[James Ziemer]]
|
|
|
|-
| [[Harvard Pilgrim|Harvard Pilgrim Health Care]]
| [[Charles D. Baker, Jr.|Charlie Baker]]
|
|
|
|-
| [[HCL Technologies]]
| [[Vineet Nayar]]
|
|
|
|-
| [[Henderson Land Development|Henderson Land Development Co. Ltd.]]
| [[Lee Shau Kee]]
|
|
|
|-
| [[Hewlett-Packard]]
| [[Mark V. Hurd]]
|
|
|
|-
| [[Hindalco]]
| [[Kumar Mangalam Birla]]
|
|
|
|-
| [[Home Depot]]
| [[Frank Blake]]
|
|
|
|-
| [[Honeywell]]
| [[David M. Cote]]
|
|
|
|-
| [[HP Hood LLC]]
| [[John A. Kaneb]]
|
|
|
|-
| [[HSBC]]
| [[Michael Geoghegan]]
|
|
|
|-
| [[IBM]]
| [[Samuel J. Palmisano]]
|
|
|
|-
| [[IKEA]]
| [[Anders Dahlvig]]
|
|
|
|-
| [[Inchcape plc]]
| [[André Lacroix (businessman)|André Lacroix]]
|
|
|
|-
| [[Infosys|Infosys Technologies Limited]]
| [[Kris Gopalakrishnan]]
|
|
|
|-
| [[Intel]]
| [[Paul Otellini]]
| CEO
| 2005
| Also serves on the board of [[Google]].<ref>http://investor.google.com/corporate/board-of-directors.html</ref>
|-
| [[ITC Limited]]
| [[Y C Deveshwar]]
| Chief Executive and Chairman of the Board<ref>http://www.itcportal.com/sets/leadership_frameset.htm</ref>
| 1996
| Has been with the company since 1968.
|-
| [[J.Crew]]
| [[Millard Drexler]]
| CEO
| 2003
| Former CEO of [[The Gap]], also director at [[Apple]]
|-
| [[Jefferies & Company]]
| [[Richard B. Handler]]
| CEO and Chairman
| 2001
|
|-
| [[JP Morgan Chase]]
| [[James Dimon]]
| CEO and Chairman
| 2004
| also on the board of the [[New York Federal Reserve]]
|-
| [[Juniper Networks]]
| [[Kevin Johnson (executive)|Kevin Johnson]]
| CEO
| 2008
| formerly of [[Microsoft]]
|-
| [[Kaplan, Inc.]]
| [[Andrew Rosen]]
|
|
|
|-
| [[Kingdom Holding Company]]
| [[Al-Waleed bin Talal]]
|
|
|
|-
| [[Koch Industries Inc.]]
| [[Charles G. Koch]]
|
|
|
|-
| [[Las Vegas Sands]]
| [[Sheldon Adelson]]
|
|
|
|-
| [[Lehman Brothers]]
| [[Richard S. (Dick) Fuld, Jr.]]
|
|
|
|-
| [[L.L. Bean]]
| [[Christopher McCormick]]
|
|
|
|-
| [[Larsen & Toubro Limited]]
| [[A M Naik]]
|
|
|
|-
| [[Lockheed Martin]]
| [[Robert Stevens]]
|
|
|
|-
| [[LPK]]
| [[Jerry Kathman]]
|
|
|
|-
| [[Macy's, Inc.]]
| [[Terry J. Lundgren]]
|
|
|
|-
| [[Manchester United F.C.|Manchester United]]
| [[David Gill (executive)|David Gill]]
|
|
|
|-
| [[Marks and Spencer]]
| [[Stuart Rose]]
|
|
|
|-
| [[McDonald's]]
| [[Jack Greenberg (McDonald's)|Jack Greenberg]]
|
|
|
|-
| [[McKinsey]]
| [[Ian Davis]]
|
|
|
|-
| [[Mercedes-Benz]]
| [[Dieter Zetsche]]
|
|
|
|-
| [[Merrill Lynch]]
| [[John Thain]]
|
|
|
|-
| [[Mesa Air Group]]
| [[Jonathan Ornstein]]
|
|
|
|-
| [[MetLife]]
| [[C. Robert Henrikson]]
|
|
|
|-
| [[MGA Entertainment]]
| [[Isaac Larian]]
|
|
|
|-
| [[Microsoft]]
| [[Steve Ballmer|Steven Anthony Ballmer]]
|
|
|
|-
| [[Mile High Comics]]
| [[Chuck Rozanski]]
|
|
|
|-
| [[Morgan Stanley]]
| [[John J. Mack]]
|
|
|
|-
| [[Motorola]]
| [[Greg Brown (businessman)|Greg Brown]]
|
|
|
|-
| [[Mozilla]]
| [[Mitchell Baker]]
|
|
|
|-
| [[MySQL AB]]
| [[Marten Mickos]]
|
|
|
|-
| [[MySpace]]
| [[Chris DeWolfe]]
|
|
|
|-
| [[National Amusements]]
| [[Sumner Redstone]]
|
|
|
|-
| [[NBC Universal, Inc.]]
| [[Jeff Zucker]]
|
|
|
|-
| [[Newlog]]
| [[Yochanan Vollach]]
|
|
|
|-
| [[News Corporation]]
| [[Rupert Murdoch|Keith Rupert Murdoch]]
|
|
|
|-
| [[New York Times Company]]
| [[Janet L. Robinson]]
|
|
|
|-
| [[NIIT]]
| [[Vijay K. Thadani]]
|
|
|
|-
| [[Nike, Inc.|Nike]]
| [[Mark Parker]]
|
|
|
|-
| [[Nissan]]
| [[Carlos Ghosn]]
|
|
|
|-
| [[Nokia]]
| [[Olli-Pekka Kallasvuo]]
|
|
|
|-
| [[Nortel]]
| [[Mike S. Zafirovski]]
|
|
|
|-
| [[Novartis]]
| [[Daniel Vasella]]
|
|
|
|-
| [[Nintendo]]
| [[Satoru Iwata]]
|
|
|
|-
| [[Office Depot]]
| [[Steve Odland]]
|
|
|
|-
| [[Oxford Sustainable Group]]
| [[Hadley Barrett]]
|
|
|
|-
| [[Oracle Corporation]]
| [[Larry Ellison]]
|
|
|
|-
| [[Orascom Telecom|Orascom Telecom Holding]]
| [[Naguib Sawiris]]
|
|
|
|-
| [[Outback Steakhouse]]
| [[Chris T. Sullivan]]
|
|
|
|-
| [[Patni Computer Systems]]
| [[Narendra Patni]]
|
|
|
|-
| [[PepsiCo]]
| [[Indra Nooyi]]
|
|
|
|-
| [[Perot Systems]]
| [[Peter Altabef]]
|
|
|
|-
| [[Pfizer]]
| [[Henry McKinnell]]
|
|
|
|-
| [[Pixar]]
| [[Steve Jobs]]
|
|
|
|-
| [[Pizza Hut]]
| [[David C. Novak]]
|
|
|
|-
| [[Playboy Enterprises]]
| [[Christie Hefner]]
|
|
|
|-
| [[Polo Ralph Lauren]]
| [[Ralph Lauren]]
|
|
|
|-
| [[Popular, Inc.]]
| [[Richard Carrión]]
|
|
|
|-
| [[Procter & Gamble]]
| [[Alan Lafley]]
|
|
|
|-
| [[Prudential Financial, Inc.]]
| [[John Strangfeld]]
|
|
|
|-
| [[Qantas|Qantas Airways Limited]]
| [[Alan Joyce (executive)|Alan Joyce]]
|
|
|
|-
| [[Qwest|Qwest Communications International]]
| [[Richard Notebaert]]
|
|
|
|-
| [[Reliance Industries Limited]]
| [[Mukesh Ambani]]
|
|
|
|-
| [[Renault]]
| [[Carlos Ghosn]]
|
|
|
|-
| [[Rite Aid Corporation]]
| [[Mary Sammons]]
|
|
|
|-
| [[Rocawear]]
| [[Jay-Z]]
|
|
|
|-
| [[Royal Ahold N.V.]]
| [[John Rishton]]
|
|
|
|-
| [[Royal Bank of Canada]]
| [[Gordon Nixon]]
|
|
|
|-
| [[Royal Bank of Scotland]]
| [[Stephen Hester]]
|
|
|
|-
| [[Royal Dutch Shell]]
| [[Peter Voser]]
|
|
|
|-
| [[Ryanair]]
| [[Michael O'Leary (Ryanair)|Michael O'Leary]]
|
|
|
|-
| [[S. C. Johnson & Son]]
| [[Herbert Fisk Johnson III]]
|
|
|
|-
| [[Saab Automobile|SAAB Automobile AB]]
| [[Jan-Åke Jonsson]]
|
|
|
|-
| [[Samsung]]
| [[Kun-Hee Lee]]
|
|
|
|-
| [[SAP AG]]
| [[Henning Kagermann]]
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| [[SAS Institute]]
| [[James Goodnight]]
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| [[Scottrade]]
| [[Rodger O. Riney]]
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| [[Seagate Technology]]
| [[Steve Luczo]]
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| [[Simon Property Group]]
| [[David Simon (CEO)|David Simon]]
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| [[Singapore Airlines]]
| [[Chew Choon Seng]]
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| [[SingTel]]
| [[Chua Sock Koong]]
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| [[Sirius Satellite Radio]]
| [[Mel Karmazin]]
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| [[Sleep Country Canada]]
| [[Steven Gunn]]
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| [[SoftBank]]
| [[Masayoshi Son]]
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| [[Southwest Airlines]]
| [[Gary C. Kelly]]
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| [[Sonic Drive-In]]
| [[J. Clifford Hudson]]
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| [[Sony]]
| [[Howard Stringer]]
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| [[Sony Computer Entertainment]]
| [[Kazuo Hirai]]
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| [[Starbucks Coffee Company]]
| [[Howard Schultz]]
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| [[Statoil]]
| [[Helge Lund]]
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| [[Sun Hung Kai|Sun Hung Kai Properties Ltd.]]
| [[Walter Kwok]]
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| [[Sun Microsystems]]
| [[Jonathan I. Schwartz]]
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| [[SunTrust Banks Inc.]]
| [[James M. Wells, III]]
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| [[Supervalu Inc.]]
| [[Jeff Noddle]]
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| [[Sulekha]]
| [[Satya Prabhakar]]
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| [[Swedbank]]
| [[Jan Lidén]]
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| [[Syntel Inc.]]
| [[Bharat Desai]]
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| [[Tata Consultancy Services]]
| [[N Chandrasekaran]]
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| [[Tata Steel]]
| [[B Muthuraman]]
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| [[Telmex]]
| [[Carlos Slim Helú]]
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| [[Telstra]]
| [[David Thodey]]
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| [[Temasek Holdings]]
| [[Ho Ching]]
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| [[Tesco PLC]]
| [[Terry Leahy|Sir Terry Leahy]] (retiring March 2011)
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| [[Thomson Reuters]]
| [[Tom Glocer]]
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| [[Tim Hortons]]
| [[Paul D. House]]
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| [[Time Warner]]
| [[Jeffrey L. Bewkes]]
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| [[TJX Companies, Inc.]]
| [[Carol Meyrowitz]]
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| [[Tracinda|Tracinda Corporation]]
| [[Kirk Kerkorian|Kerkor "Kirk" Kerkorian]]
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| [[The Siegel Group|The Siegel Group Nevada, Inc]]
| [[Steve Siegel|Stephen Siegel]]
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| [[The Travelers Companies]]
| [[Jay S. Fishman]]
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| [[Trump Organization]]
| [[Donald Trump]]
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| [[Toyota]]
| [[Hiroshi Okuda]]
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| [[Toys for Bob]]
| [[Paul Reiche III]]
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| [[Toys "R" Us]]
| [[Gerald L. Storch]]
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| [[Tradeking]]
| [[Donato A. Montanaro]]
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| [[Turner Broadcasting System, Inc.]]
| [[Philip I. Kent]]
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| [[Twitter]]
| [[Jack Dorsey]]
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| [[Tyson Foods, Inc.]]
| [[Richard L. Bond]] (former)
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| [[UAL Corporation]]
| [[Glenn F. Tilton]]
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| [[UBS AG]]
| [[Oswald Grübel]]
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| [[U.S. Century Bank]]
| [[Octavio Hernández]]
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| [[US Airways]]
| [[Doug Parker (airline executive)|Doug Parker]]
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| [[United Parcel Service]]
| [[D. Scott Davis]]
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| [[US Bancorp]]
| [[Richard K. Davis]]
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| [[UGI Corp.]]
| [[Lon R. Greenberg]]
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| [[United States Steel Corp.]]
| [[John P. Surma]]
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| [[United Technologies]]
| [[Louis R. Chênevert]]
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| [[Valero Energy Corporation]]
| [[William R. Klesse]]
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| [[Verizon]]
| [[Ivan Seidenberg]]
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| [[Viacom]]
| [[Philippe Dauman|Philippe P. Dauman]]
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| [[Viking Range]]
| [[Fred Carl, Jr.]]
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| [[Vodafone]]
| [[Vittorio Colao]]
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| [[Volkswagen]]
| [[Martin Winterkorn]]
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| [[Vulcan Inc.]]
| [[Paul Allen]]
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| [[The Walt Disney Company|Walt Disney Company, The]]
| [[Robert Iger]]
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| [[Walgreen Company]]
| [[Gregory Wasson]]
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| [[Wal-Mart]]
| [[Mike Duke]]
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| [[Warner Bros.]]
| [[Barry Meyer]]
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| [[Washington Mutual]]
| [[Kerry Killinger]]
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| [[The Washington Post Company]]
| [[Donald Graham]]
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| [[Whole Foods Market]]
| [[John Mackey (businessman)|John Mackey]]
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| [[Wikia, Inc.]]
| [[Gil Penchina]]
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| [[Windstream Corporation]]
| [[Jeffery Gardner]]
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| [[Winn-Dixie Stores]]
| [[Peter Lynch]]
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| [[Wipro Technologies]]
| [[Girish Paranjpe]] and [[Suresh Vaswani]]
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| [[World Wrestling Entertainment]]
| [[Vince McMahon]]
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| [[Yahoo!]]
| [[Carol Bartz]]
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| [[YG Entertainment]]
| [[Yang Hyun Suk]]
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| [[Young Money Entertainment]]
| [[Lil Wayne]]
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| [[YouTube, LLC]]
| [[Chad Hurley]]
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| [[Yum! Brands, Inc.]]
| [[David C. Novak]]
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|}

== References ==
{{reflist}}

[[Category:Lists of businesspeople|CEO]]

[[ca:Llista d'executius en cap]]

Charcot–Marie–Tooth disease

2010-05-26T15:00:53Z

PhineasG: /* Diagnosis */ clarified methods of the whole genome sequencing study: only one patient's genome was sequenced, not all family members'.

{{Infobox disease |
Name = Charcot-Marie-Tooth disease |
Image = Charcot-marie-tooth foot.jpg |
Caption = The foot of a person with Charcot-Marie-Tooth. The lack of muscle, a high arch, and hammer toes are signs of the genetic disease. |
DiseasesDB = 5815 |
DiseasesDB_mult= {{DiseasesDB2|2343}} |
ICD10 = {{ICD10|G|60|0|g|60}} |
ICD9 = {{ICD9|356.1}} |
ICDO = |
OMIM = |
MedlinePlus = 000727 |
eMedicineSubj = orthoped |
eMedicineTopic = 43 |
eMedicine_mult = {{eMedicine2|pmr|29}} |
MeshID = D002607 |
}}
'''Charcot-Marie-Tooth disease''' ('''CMT'''), known also as '''Charcot-Marie-Tooth neuropathy''', '''hereditary motor and sensory neuropathy''' ('''HMSN'''), '''hereditary sensorimotor neuropathy''' ('''HSMN'''), or '''peroneal muscular atrophy''', is an inherited disorder of [[nerve]]s ([[neuropathy]]) that takes different forms. It is characterized by loss of muscle tissue and touch sensation, predominantly in the feet and legs but also in the hands and arms in the advanced stages of disease. Presently incurable, this disease is one of the most common inherited neurological disorders, with 36 in 100,000 affected.<ref name=Krajewski>{{cite journal |author=Krajewski KM, Lewis RA, Fuerst DR, ''et al.'' |title=Neurological dysfunction and axonal degeneration in Charcot-Marie-Tooth disease type 1A |journal=Brain |volume=123 ( Pt 7) |issue= |pages=1516–27 |year=2000 |pmid=10869062 |doi= 10.1093/brain/123.7.1516|url=http://brain.oxfordjournals.org/cgi/content/full/123/7/1516#SEC4}}</ref>

==Molecular causes==

Several proteins are essential for the normal function of nerve cells ([[neurons]]). Charcot-Marie-Tooth disease is caused by mutations that cause defects in any of these proteins. Nerve signals are conducted by an [[axon]] with a [[myelin]] sheath wrapped around it. Most mutations in CMT affect the myelin sheath. Some affect the axon.

Some mutations affect the gene [[MFN2]], which is a mitochondrial gene. Cells contain separate sets of genes in their [[nucleus]] and in their [[mitochondria]]. In nerve cells, the mitochondria travel down the long axons. In some forms of CMT, mutated [[MFN2]] causes the mitochondria to form large clusters, or clots, which are unable to travel down the axon towards the [[synapses]]. This prevents the synapses from functioning.<ref name="Baloh">{{cite journal |author=Baloh RH, Schmidt RE, Pestronk A, Milbrandt J |title=Altered axonal mitochondrial transport in the pathogenesis of Charcot-Marie-Tooth disease from mitofusin 2 mutations |journal=J. Neurosci. |volume=27 |issue=2 |pages=422–30 |year=2007 |pmid=17215403 |doi=10.1523/JNEUROSCI.4798-06.2007 |url=http://www.jneurosci.org/cgi/content/abstract/27/2/422}}</ref>

CMT is divided into the primary demyelinating neuropathies (CMT1, CMT3, and CMT4) and the primary axonal neuropathies (CMT2), with frequent overlap. Another cell involved in CMT is the [[Schwann cell]], which creates the myelin sheath, by wrapping its plasma membrane around the axon in a structure that is sometimes compared to a [[swiss roll]].<ref name=Berger>{{cite journal |author=Berger P, Young P, Suter U |title=Molecular cell biology of Charcot-Marie-Tooth disease |journal=Neurogenetics |volume=4 |issue=1 |pages=1–15 |year=2002 |pmid=12030326 |doi= 10.1007/s10048-002-0130-z|url=http://link.springer.de/link/service/journals/10048/bibs/2004001/20040001.htm}}</ref>

Neurons, Schwann cells, and [[fibroblast]]s work together to create a working nerve. Schwann cells and neurons exchange molecular signals that regulate survival and differentiation. These signals are disrupted in CMT.<ref name=Berger/>

Demyelinating Schwann cells causes abnormal axon structure and function. They may cause axon degeneration. Or they may simply cause axons to malfunction.<ref name=Krajewski/>

The myelin sheath allows nerve cells to conduct signals faster. When the myelin sheath is damaged, nerve signals are slower, and this can be measured by a common neurological test, [[electromyography]].

When the axon is damaged, on the other hand, this results in a reduced compound muscle [[action potential]] (CMAP).<ref>http://www.ingentaconnect.com/content/bsc/jns/2008/00000013/00000003/art00008</ref>

==Symptoms==
Symptoms usually begin in late childhood or early adulthood. Some people don't experience symptoms until the early thirties. Usually, the initial symptom is [[foot drop]] early in the course of the disease. This can also cause [[hammer toe]], where the toes are always curled. Wasting of muscle tissue of the lower parts of the legs may give rise to "stork leg" or "inverted bottle" appearance. Weakness in the hands and forearms occurs in many people later in life as the disease progresses.

Symptoms and progression of the disease can vary. Breathing can be affected in some; so can hearing, vision, and the neck and shoulder muscles. [[Scoliosis]] is common. [[Acetabulum|Hip sockets]] can be malformed. Gastrointestinal problems can be part of CMT, as can chewing, swallowing, and speaking (as [[vocal cords]] atrophy). A [[tremor]] can develop as muscles waste. [[Pregnancy]] has been known to exacerbate CMT, as well as extreme emotional stress.

==Diagnosis==
CMT can be diagnosed through symptoms, through measurement of the speed of nerve impulses ([[electromyography]]), through [[biopsy]] of the nerve, and through DNA testing. DNA testing can give a definitive diagnosis, but not all the [[genetic marker]]s for CMT are known.

In 2010, CMT was one of the first diseases where the genetic cause of a particular patient's disease was precisely determined by sequencing the whole genome of an affected individual.<ref name="NYT2010">{{cite web |url=http://www.nytimes.com/2010/03/11/health/research/11gene.html?hp |title =Disease Cause Is Pinpointed With Genome |author=NICHOLAS WADE |publisher=New York Times |date=2010-3-10}}</ref><ref>{{cite journal
|author=James R. Lupski, et al.
|title=Whole-Genome Sequencing in a Patient with Charcot–Marie–Tooth Neuropathy
|journal=N Engl J Med
|volume=362
|issue=
|pages=
|year=2010
|pmid=20220177
|doi=10.1056/NEJMoa0908094
|url=http://content.nejm.org/cgi/content/full/NEJMoa0908094
}}Free full text</ref> Two mutations were identified in a gene, SH3TC2, known to cause CMT, and were then looked for in the patient's mother, father, and seven siblings with and without the disease. The mother and father each had one good and one bad copy of this gene, and had mild or no symptoms. The offspring that inherited two bad copies had the full-blown disease. Sequencing the initial patient's whole genome cost $50,000, but researchers estimated that it would soon cost $5,000 and become common.

==Types==

As of early 2010, mutations in 39 genes have been identified as causes of CMT.<ref name="NYT2010"/> CMT can be categorized first into major clinical categories, and then into subtypes according to those mutations. Type 1 primarily affects the myelin sheath, and is either dominant, recessive or X-linked. Type 2 primarily affects the axon, and is either dominant or recessive. Other types are mixed.<ref>NEJM Lupski</ref>

'''Clinical categories'''
{| class="wikitable"
|-
! Name
! Inheritance
! Frequency
! Notes
|-
| CMT Type 1 (CMT1)
| [[Autosomal dominant]]
| Type 1 affects approximately 80% of CMT patients and is the most common type of CMT. The subtypes share clinical symptoms.
| Causes demyelination, which can be detected by measuring nerve conduction velocities.
|-
| CMT Type 2 (CMT2)
| [[Autosomal dominant]] (except CMT2B1)
| Type 2 affects approximately 20-40% of CMT patients.
| Main effect is on the axon. The average [[nerve conduction velocity]] is slightly below normal, but generally above 38[[Metre per second|m/s]]
|-
| CMT Type 3 (CMT3)
| [[Autosomal recessive]]
| Type 3 affects very few CMT patients.
|rowspan=2|
|-
| CMT Type 4 (CMT4)
| [[Autosomal recessive]]
| Type 4 affects very few CMT patients.
|-
| CMT X-Linked (CMTX)
| [[Dominant gene|X-linked dominant]]
| CMTX affects approximately 10-20% of CMT patients.
| Approx 10% of X-linked CMT patients have some other form than CMTX. However a study published in 1997 indicates that a connexin 32 gene mutation is associated with this form which may be more common than previously thought.<ref>{{cite journal |author=Latour P, Fabreguette A, Ressot C, ''et al.'' |title=New mutations in the X-linked form of Charcot-Marie-Tooth disease |journal=Eur. Neurol. |volume=37 |issue=1 |pages=38–42 |year=1997 |pmid=9018031 |doi= 10.1159/000117403|url=}}</ref><ref>{{cite book| author = Andrew L Harris and Darren Locke | title = Connexins, A Guide | publisher = Springer | date = 2009 | location = New York | pages = 574 | url = http://www.springer.com/978-1-934115-46-6 | isbn = 978-1-934115-46-6}}</ref>
|}

'''Genetic subtypes'''
{| class="wikitable" class="sortable wikitable"
| '''Type''' || '''[[OMIM]]''' || '''Gene ''' || '''[[Locus (genetics)|Locus]]''' || '''Description'''
|-
| CMT1A || {{OMIM2|118220}} || ''[[PMP22]]'' || 17p11.2 || The most common form of the disease, 70-80% of Type 1 patients. Average [[Nerve conduction velocity|NCV]]: 20-25[[Metre per second|m/s]] when associated with essential tremor and ataxia, called Roussy-Levy Syndrome {{OMIM2|180800}}
|-
| CMT1B || {{OMIM2|118200}} || ''[[MPZ]]'' || 1q22 || Caused by mutations in the gene producing [[protein zero]] (P0). 5-10% of Type 1 patients. Average [[Nerve conduction velocity|NCV]]: <15[[Metre per second|m/s]]
|-
| CMT1C || {{OMIM2|601098}} || ''[[LITAF]]'' || 16p13.1-p12.3 || Causes severe [[myelin|demyelination]], which can be detected by measuring nerve conduction velocities. Usually shows up in infancy. Average [[Nerve conduction velocity|NCV]]: 26-42[[Metre per second|m/s]]. Identical symptoms to CMT-1A.
|-
| CMT1D || {{OMIM2|607678}} || ''[[EGR2]]'' || 10q21.1-q22.1 || Average [[Nerve conduction velocity|NCV]]: 15-20[[m/s]]
|-
| CMT1E || {{OMIM2|118300}} || ''[[PMP22]]'' || 17p11.2 || [[Demyelinating]], [[deafness]]
|-
| CMT2A || {{OMIM2|118210}} || [[MFN2]] or [[KIF1B]] || 1p36 || The cause is likely located on chromosome 1 for the mitofusion 2 protein. Some research has also linked this form of CMT to the protein kinesin 1B. Does not show up on nerve conduction velocity tests, because it is caused by [[axonopathy]].
|-
| CMT2B || {{OMIM2|600882}} || RAB7 (''[[RAB7A]]'', ''[[RAB7B]]'') || 3q21. ||
|-
| CMT2B1 || {{OMIM2|605588}} || ''[[LMNA]]'' || 1q22 || axonal CMT, ([[Laminopathies|laminopathy]])
|-
| CMT2B2 || {{OMIM2|605589}} ||''[[ MED25]]'' || 19q13.3 ||
|-
| CMT2C || {{OMIM2|606071}} ||'[[ TRPV4 ]]'' || 12q23-q24 || May cause vocal cord, diaphragm, and distal weaknesses.
|-
| CMT2D || {{OMIM2|601472}} || [[GARS]] || 7p15 || Patients with mutations in the GARS gene tend to have more severe symptoms in the upper extremities (hands), which is atypical for CMT in general.
|-
| CMT2E || {{OMIM2|607684}} || [[NEFL]] || 8p21 ||
|-
| CMT2F || {{OMIM2|606595}} || ''[[HSPB1]]'' || 7q11-q21 ||
|-
| CMT2G || {{OMIM2|608591}} || || 12q12-13 ||
|-
| CMT2H || {{OMIM2|607731}} || [[GDAP1]] || 8q13-q21.1 ||
|-
| CMT2J || {{OMIM2|607736}} || ''[[MPZ]]'' || 1q22 ||
|-
| CMT2K || {{OMIM2|607831}} ||''[[GDAP1]] '' || 8q13-q21.1 ||
|-
| CMT2L || {{OMIM2|608673}} || ''[[HSPB8]]'' || 12q24 ||
|-
| CMT3 || {{OMIM2|145900}} || varies || varies || Sometimes called [[Dejerine-Sottas disease]]. Rarely found. Average [[Nerve conduction velocity|NCV]]: Normal (50-60m/s). This is an old classification. Currently this is referred to as CMT4F.{{fact|date=May 2009}}
|-
| CMT4A || {{OMIM2|214400}} || [[GDAP1]] || 8q13-q21.1 ||
|-
| CMT4B1 || {{OMIM2|601382}} || [[MTMR2]] || 11q22 ||
|-
| CMT4B2 || {{OMIM2|604563}} || CMT4B2 ([[SBF2]]) || 11p15 || May be called "SBF2/MTMR13".
|-
| CMT4C || {{OMIM2|601596}} || KIAA1985 ([[SH3TC2]]) || 5q32 || May lead to respiratory compromise.
|-
| CMT4D || {{OMIM2|601455}} || [[NDRG1]] || 8q24.3 || [[Demyelinating]], [[deafness]]
|-
| CMT4E || {{OMIM2|605253}} || ''[[EGR2]]'' || 10q21.1-10q22.1 || "CMT4E" is a tentative name
|-
| CMT4F || {{OMIM2|145900}} || [[PRX (gene)|PRX]] || 19q13.1-19q13.2 || "CMT4F" is a tentative name
|-
| CMT4H || {{OMIM2|609311}} || [[FGD4]] || 12p11.21 ||
|-
| CMT4J || {{OMIM2|611228}} || KIAA0274 ([[FIG4]]) || 6q21 ||
|-
| CMTX1 || {{OMIM2|302800}} || ''[[GJB1]]'' || Xq13.1 || Average [[Nerve conduction velocity|NCV]]: 25-40[[Metre per second|m/s]]
|-
| CMTX2 || {{OMIM2|302801}} || || Xq22.2 ||
|-
| CMTX3 || {{OMIM2|302802}} || Unknown, but 11 of 15 eliminated<ref name="pmid18458969">{{cite journal |author=Brewer M, Changi F, Antonellis A, ''et al.'' |title=Evidence of a founder haplotype refines the X-linked Charcot-Marie-Tooth (CMTX3) locus to a 2.5 Mb region |journal=Neurogenetics |volume=9 |issue=3 |pages=191–5 |year=2008 |month=July |pmid=18458969 |doi=10.1007/s10048-008-0126-4}}</ref> || Xq26 ||
|-
| CMTX4 || {{OMIM2|310490}} || || Xq24-q26.1 || Known as Cowchock syndrome
|-
| CMTX5 || {{OMIM2|311070}} || || Xq22-q24 || Known as Rosenberg-Chutorian syndrome. Signs include optic atrophy, polyneuropathy and deafness
|
|}

==Management and treatment==
Although there is no current standard treatment, the use of [[ascorbic acid]] has been proposed, and has shown some benefit in animal models.<ref name="pmid15034573">{{cite journal |author=Passage E, Norreel JC, Noack-Fraissignes P, ''et al.'' |title=Ascorbic acid treatment corrects the phenotype of a mouse model of Charcot-Marie-Tooth disease |journal=Nat. Med. |volume=10 |issue=4 |pages=396–401 |year=2004 |pmid=15034573 |doi=10.1038/nm1023}}</ref> A clinical trial to determine the effectiveness of high doses of ascorbic acid (vitamin C) in treating humans with CMT type 1A has been conducted.<ref>{{cite web |url=http://www.mda.org/research/view_ctrial.aspx?id=186 |title=Clinical Trials - Neuromuscular Trial/Study |date=2007-07-18 |accessdate=2008-05-28}}</ref> The results of the trial upon children have shown that a high dosage intake of ascorbic acid is safe but the efficacy endpoints expected were not met.<ref>{{cite journal | last= Burns | first= Joshua | coauthors= Robert Ouvrier, Eppie Yiu, Pathma Joseph, Andrew Kornberg, Michael Fahey, Monique Ryan | year= 2009 | month= June | title= Ascorbic acid for Charcot—Marie—Tooth disease type 1A in children: a randomised, double-blind, placebo-controlled, safety and efficacy trial | journal= The Lancet Neurology | volume= 8 | issue= 6 |pages= 537–544 | doi= 10.1016/S1474-4422(09)70108-5 | accessdate = 23 May 2009}}</ref>

People who have CMT are advised to maintain a healthy weight, because extra weight can limit mobility and places additional stress on the joints. They are also advised to be moderately physically active, and to pay special attention to the maintenance of their strength and flexibility. Water therapy is particularly beneficial, since the stress put on the joints is minimized.

The Charcot-Marie-Tooth Association classifies the [[chemotherapy]] drug [[vincristine]] as a "definite high risk" and states that "vincristine has been proven hazardous and should be avoided by all CMT patients, including those with no symptoms."<ref>[http://www.charcot-marie-tooth.org/med_alert.php CMT Association: Medical Alert]</ref>

There are also several corrective surgical procedures that can be done to improve physical condition.

Genetic testing is available for many of the different types of Charcot-Marie-Tooth and may help guide treatment.

== History ==

The disease is named for those who classically described it: [[Jean-Martin Charcot]] (1825-1893), his pupil [[Pierre Marie]] (1853-1940) (''"Sur une forme particulière d'atrophie musculaire progressive, souvent familiale débutant par les pieds et les jambes et atteignant plus tard les mains"'', Revue médicale, Paris, 1886; 6: 97-138.), and [[Howard Henry Tooth]] (1856-1925) ("The peroneal type of progressive muscular atrophy", dissertation, London, 1886.)

== See also ==
* [[Palmoplantar keratoderma and spastic paraplegia]]

==References==
{{reflist|2}}

==External links==
*[http://www.charcot-marie-tooth.org/ Charcot Marie Tooth Association]
*[http://www.charcotmarietooth.webs.com CMT Central - An Insight into CMT] - Sourced info on CMT, by and for people with CMT
*[http://neurology.med.wayne.edu/neurogenetics/na_database.php Charcot Marie Tooth North American Database] - patients with CMT who do not live in North America are also encouraged to join
*[http://www.mdausa.org/ Muscular Dystrophy Association] - Although CMT is not a form of Muscular Dystrophy, it is one of several non-muscular dystrophy diseases for which the MDA offers support
*[http://www.muscle.ca/ Muscular Dystrophy Canada]
*[http://www.hnf-cure.org/ Hereditary Neuropathy Foundation]
*[http://www.cmt.org.uk/ CMT United Kingdom]
*[http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=cmt GeneReviews/NCBI/NIH/UW entry on Charcot-Marie-Tooth Hereditary Neuropathy Overview]
* {{DMOZ|Health/Conditions_and_Diseases/Neurological_Disorders/Peripheral_Nervous_System/Charcot-Marie-Tooth_Disease/}}

{{PNS diseases of the nervous system}}

[[Category:Neurological disorders]]
[[Category:Genetic disorders]]

{{DEFAULTSORT:Charcot-Marie-Tooth Disease}}

[[ca:Malaltia de Charcot-Marie-Tooth]]
[[de:Morbus Charcot-Marie-Tooth]]
[[et:Pärilik motoorne ja sensoorne neuropaatia]]
[[es:Síndrome de Charcot–Marie–Tooth]]
[[fa:شارکو ماری توث]]
[[fr:Maladie de Charcot-Marie-Tooth]]
[[ko:샤르코 마리 투스 질환]]
[[it:Malattia di Charcot-Marie-Tooth]]
[[nl:Hereditaire motorische en sensorische neuropathieën]]
[[ja:シャルコー・マリー・トゥース病]]
[[no:Charcot-Marie-Tooths sykdom]]
[[pms:Maladìa ëd Charcot-Marie-Tooth]]
[[pl:Choroba Charcota-Mariego-Tootha]]
[[pt:Doença de Charcot-Marie-Tooth]]
[[sv:Charcot-Marie-Tooths sjukdom]]

Evil Hearted You

2010-02-10T23:46:27Z

PhineasG:

{{Infobox Single 
| Name = Evil Hearted You
| Cover =
| Cover size =
| Caption =
| Artist = [[The Yardbirds]]
| from Album =
| A-side =
| B-side = "Still I'm Sad" (McCarty, Samwell-Smith)
| Released = October 1965
| Format = [[7" single]]
| Recorded =
| Genre = [[Pop music]]
| Length =
| Label = Columbia DB7706 (UK)
| Writer = [[Graham Gouldman]]
| Producer = [[Giorgio Gomelsky]]
| Certification =
| Last single = "[[Heart Full of Soul]]" (1965)
| This single = "Evil Hearted You" (1965)
| Next single = "[[Shapes of Things]]" (1966) -- "[[I'm a Man (Bo Diddley song)|I'm a Man]]" (USA, 1965)
| Misc =
}}
'''"Evil Hearted You"''' is a 1965 single by the [[British Invasion]] band [[The Yardbirds]]. It charted at #3 in the UK. The single was not released in the USA, but was featured on the compilation albums "[[Having a Rave Up]]" and "[[Shapes of Things (album)|Shapes of Things]]".

The song is probably most known for its guitar solo featuring [[Spanish scale]]s, which were highly unusual for 1965.

The song was later covered by the [[Pixies]], who redid the lyrics entirely in Spanish. This version appears as a B-Side on ''[[Planet of Sound]]'' (1991) and can also be found on Pixies' ''[[Complete 'B' Sides]]'' album.

[[Category:1965 singles]]
[[Category:The Yardbirds songs]]
[[Category:Songs written by Graham Gouldman]]
{{1960s-song-stub}}

Evil Hearted You

2010-02-10T23:46:09Z

PhineasG:

{{Infobox Single 
| Name = Evil Hearted You
| Cover =
| Cover size =
| Caption =
| Artist = [[The Yardbirds]]
| from Album =
| A-side =
| B-side = "Still I'm Sad" (McCarty, Samwell-Smith)
| Released = October 1965
| Format = [[7" single]]
| Recorded =
| Genre = [[Pop music]]
| Length =
| Label = Columbia DB7706 (UK)
| Writer = [[Graham Gouldman]]
| Producer = [[Giorgio Gomelsky]]
| Certification =
| Last single = "[[Heart Full of Soul]]" (1965)
| This single = "Evil Hearted You" (1965)
| Next single = "[[Shapes of Things]]" (1966) -- "[[I'm a Man (Bo Diddley song)|I'm a Man]]" (USA, 1965)
| Misc =
}}
'''"Evil Hearted You"''' is a 1965 single by the [[British Invasion]] band [[The Yardbirds]]. It charted at #3 in the UK. The single was not released in the USA, but was featured on the compilation albums "[[Having a Rave Up]]" and "[[Shapes of Things|Shapes of Things (album)]]".

The song is probably most known for its guitar solo featuring [[Spanish scale]]s, which were highly unusual for 1965.

The song was later covered by the [[Pixies]], who redid the lyrics entirely in Spanish. This version appears as a B-Side on ''[[Planet of Sound]]'' (1991) and can also be found on Pixies' ''[[Complete 'B' Sides]]'' album.

[[Category:1965 singles]]
[[Category:The Yardbirds songs]]
[[Category:Songs written by Graham Gouldman]]
{{1960s-song-stub}}

Evil Hearted You

2010-02-10T23:44:50Z

PhineasG:

{{Infobox Single 
| Name = Evil Hearted You
| Cover =
| Cover size =
| Caption =
| Artist = [[The Yardbirds]]
| from Album =
| A-side =
| B-side = "Still I'm Sad" (McCarty, Samwell-Smith)
| Released = October 1965
| Format = [[7" single]]
| Recorded =
| Genre = [[Pop music]]
| Length =
| Label = Columbia DB7706 (UK)
| Writer = [[Graham Gouldman]]
| Producer = [[Giorgio Gomelsky]]
| Certification =
| Last single = "[[Heart Full of Soul]]" (1965)
| This single = "Evil Hearted You" (1965)
| Next single = "[[Shapes of Things]]" (1966) -- "[[I'm a Man (Bo Diddley song)|I'm a Man]]" (USA, 1965)
| Misc =
}}
'''"Evil Hearted You"''' is a 1965 single by the [[British Invasion]] band [[The Yardbirds]]. It charted at #3 in the UK. The single was not released in the USA, but was featured on the compilation albums "[[Having a Rave Up]]" and "[[Shapes of Things]]".

The song is probably most known for its guitar solo featuring [[Spanish scale]]s, which were highly unusual for 1965.

The song was later covered by the [[Pixies]], who redid the lyrics entirely in Spanish. This version appears as a B-Side on ''[[Planet of Sound]]'' (1991) and can also be found on Pixies' ''[[Complete 'B' Sides]]'' album.

[[Category:1965 singles]]
[[Category:The Yardbirds songs]]
[[Category:Songs written by Graham Gouldman]]
{{1960s-song-stub}}

Hiccup

2008-06-12T13:47:49Z

PhineasG: /* Medical treatment */ wrong url given for reference 5

{{expert-subject|health}}
{{Cleanup|date=May 2007}}
{{for|information on Hydrophobic Interaction Chromatography|Chromatography}}
{{Infobox_Symptom
| Name = Singultus
| Background =
| Image =
| Caption =
| ICD10 = {{ICD10|R|06|6|r|00}}
| ICD9 = {{ICD9|786.8}}
| ICDO =
| OMIM =
| DiseasesDB =
| MedlinePlus =
| eMedicineSubj =
| eMedicineTopic =
}}
A '''hiccup''' or '''hiccough''' (normally pronounced "HICK-up" {{IPAEng|ˈhɪkʌp}}, though hiccough is an archaic and now disused spelling), is a spasmodic contraction of the [[Diaphragm (anatomy)|diaphragm]] that typically repeats several times per minute. In [[human]]s, the abrupt rush of [[air]] into the [[lungs]] causes the [[epiglottis]] to close, creating the "hic" {{Audio|Hiccupsound.ogg|listen}} noise. In [[medicine]], it is known as '''synchronous diaphramatic flutter''' (SDF), or ''singultus''. The term "hiccup" is also used to describe a small and unrepeated aberration in an otherwise consistent pattern.

A bout of hiccups generally resolves itself without intervention, although many [[home remedy|home remedies]] claim to shorten the duration, and medication is occasionally necessary.

==Causes==

While many cases develop spontaneously, hiccups are known to be triggered by specific events, such as eating too quickly, being hungry for long, taking a cold drink while eating a hot meal, belching, eating very hot or spicy food, laughing vigorously or coughing, drinking [[alcoholic beverages]] in excess, crying out loud (sobbing causes air to enter the stomach), some smoking situations where abnormal inhalation can occur (in tobacco or other smoke like cannabis, perhaps triggered by precursors to coughing), [[electrolyte]] imbalance, talking too long, clearing the throat, or from lack of vitamins. Hiccups may be caused by pressure to the [[phrenic nerve]] by other anatomical structures, or having the sensation that there is food in the esophagus, rarely by [[tumor]]s and certain kidney disease. The [[American Cancer Society]] reports that 30% of [[chemotherapy]] patients suffer singultus as a side effect of treatment.

===Phylogenetic hypothesis===

Christian Straus and co-workers at the Respiratory Research Group, [[University of Calgary]], [[Canada]], propose that the hiccup is an [[evolution]]ary remnant of earlier [[amphibian]] [[Respiratory system|respiration]]; amphibians such as [[frog]]s gulp [[air]] and [[water]] via a rather simple motor reflex akin to [[mammal]]ian hiccuping.<ref name=Straus> {{cite journal|title=A phylogenetic hypothesis for the origin of hiccough.|journal=BioEssays|date=2003 Feb|first=C.|last=Straus|volume=25|issue=2|pages=182-188|id=10.1002/bies.10224 |url=http://www3.interscience.wiley.com/cgi-bin/abstract/102526391/ABSTRACT?CRETRY=1&SRETRY=0=Abstract|format=|accessdate=2007-07-20}}</ref> In support of this idea, they observe that the motor pathways that enable hiccuping form early during [[fetus|fetal]] development, before the motor pathways that enable normal [[lung]] ventilation form; thus according to [[recapitulation theory]] the hiccup is [[evolution]]arily antecedent to modern [[lung]] [[Respiratory system|respiration]]. Additionally, they point out that hiccups and [[amphibian]] gulping are inhibited by elevated [[CO2|CO2]] and can be completely stopped by the drug [[Baclofen]] (a [[GABA B receptor|GABAB]] [[Sensory receptor|receptor]] [[agonist]]), illustrating a shared physiology and [[evolution]]ary heritage. These proposals would explain why [[Premature birth|premature infants]] spend 2.5% of their time hiccuping, indeed they are gulping just like [[amphibian]]s, as their [[lung]]s are not yet fully formed.<ref name='Kahrilas'> {{cite journal|title=Why do we hiccup?|journal=Gut|date=1997 Nov|first=P.J.|last=Kahrilas|volume=41|issue=5|pages=712-713|url=http://gut.bmj.com/cgi/content/extract/41/5/712|format=|accessdate=2007-07-20}}</ref>

===Amniotic/atmospheric hypothesis===

[[Medical ultrasonography|Ultrasound scans]] have also shown that babies in-utero experience hiccups. The amniotic/atmospheric hypothesis suggests that hiccups are a muscle exercise for the respiratory system prior to birth, or that they prevent amniotic fluid from entering the lungs.<ref>Randerson, James, [http://www.newscientist.com/article.ns?id=dn3355 Tadpoles take blame for human hiccups], [[New Scientist]], Feb. 3, 2003</ref> The amniotic/atmospheric hypothesis holds that there are two distinct systems in the brain for controlling [[Respiration (physiology)|respiration]]: one that is used when the [[fetus]] is respiring [[amniotic fluid]] during its time in the [[womb]], and another that only comes into use following birth, used for breathing air. Since amniotic fluid is much more viscous than air, a much greater effort is required from the [[Thoracic diaphragm| diaphragm]] to inhale it. If this amniotic breathing system becomes dominant for any reason during life outside the womb, the result will be a momentary, very forceful effort at inhalation. The body senses that things are not correct, and since so much force is actually dangerous to the [[lungs]] and other organs, the system is immediately preempted and switched back to the atmospheric system. However, this preemptive control gradually relaxes, making the phenomenon [[Periodicity|cyclic]] as long as there is underlying activation of the amniotic respiration system: as the preemptive control falls below the threshold, the amniotic routine resumes control, only to be preempted again, and this cycle continues until the underlying conditions leading to the amniotic breathing activation revert to their normal state – at which point the hiccups stop. This theory is supported by the finding that hiccups are more common in premature newborns, as in these cases the atmospheric respiration system is less prepared to take precedence over the amniotic respiration system.

==Treatment==

Ordinary hiccups are cured easily without medical intervention; in most cases they can be stopped simply by forgetting about them. However, there are a number of anecdotally prescribed treatments for casual cases of hiccups (see Home Remedies below). Some of the more common home remedies include: scaring the afflicted, drinking water (sometimes in an unorthodox manner), and altering one's breathing.

===Medical treatment===

Hiccups are treated medically only in severe and persistent (termed "intractable") cases, such as in the case of a 15 year old girl who in 2007 hiccuped continuously for five weeks.<ref>{{cite news
| title = Teen's hiccups stop after five weeks
| publisher = ABC News Online
| date = 2007-03-02
| url = http://www.abc.net.au/news/newsitems/200703/s1861793.htm
| accessdate = }}</ref> [[Haloperidol]] (Haldol, an anti-psychotic and sedative), [[metoclopramide]] (Reglan, a gastrointestinal stimulant), and [[chlorpromazine]] (Thorazine, an anti-psychotic with strong sedative effects) are used in cases of intractable hiccups. In severe or resistant cases, [[baclofen]], an anti-spasmodic, is sometimes required to suppress hiccups. Effective treatment with sedatives often requires a dose that renders the person either unconscious or highly lethargic. Hence, medicating singultus is done short-term, as the affected individual cannot continue with normal life activities while taking the medication.

Persistent and intractable hiccups due to [[electrolyte]] imbalance ([[hypokalemia]], [[hyponatremia]]) may benefit from drinking a carbonated beverage containing salt to normalize the potassium-sodium balance in the nervous system. The carbonation promotes quicker absorption.

The administration of intranasal vinegar is thought to be safe and handy method to stimulate dorsal wall of nasopharynx, where the pharyngeal branch of the glossopharyngeal nerve (afferent of the hiccup reflex arc) is distributed.<ref name="Iwasaki">{{cite journal
| last = Iwasaki
| first = N
| coauthors= et al.
| title = Hiccup treated by administration of intranasal vinegar
| journal = No To Hattatsu
| volume = 39
| issue = 3
| pages = 202-5
| publisher =
| date = 2007 May
| url =
| accessdate = 2008-04-24}}</ref>

Dr. [[Bryan R. Payne]], a neurosurgeon at the [[Louisiana State University]] Health Sciences Center in [[New Orleans]], has had some success with an experimental new procedure in which a vagus nerve stimulator is implanted in the upper chest of patients with an intractable case of hiccups. "It sends rhythmic bursts of [[electricity]] to the [[brain]] by way of the [[vagus nerve]], which passes through the neck. The [[Food and Drug Administration]] approved the vagus nerve stimulator in 1997 as a way to control seizures in some patients with [[epilepsy]]. In [[2005]], the agency endorsed the use of the stimulator as a treatment of last resort for people with severe [[clinical depression|depression]]."<ref>{{cite news
| last = Schaffer
| first = Amanda
| title = A Horrific Case of Hiccups, a Novel Treatment
| publisher = [[New York Times]]
| date = 2006-01-10
| url = http://www.nytimes.com/2006/01/10/health/10hicc.html
| accessdate = 2008-04-24}}</ref>

===Home remedies===
{{Unreferenced|date=May 2007}}
{{SectOR|date=February 2008}}









The following are some commonly suggested home remedies. While numerous remedies are offered, they mostly fall into a few broad categories. These categories include purely [[psychosomatic]] cures centered around relaxation and distraction, cures involving swallowing and eating (with the rationale generally that this would remove irritants or reset mechanisms in the affected region), and cures involving controlled/altered breathing.

The first two categories may prove effective for many short lived and minor cases of hiccups. For instance, with an assistant applying pressure to one's ears, drinking any quantity of liquid whilst holding one's nose is a common home remedy for hiccups. However, those suffering from an intractable case may become desperate sorting through various ineffective home remedies. Many of the cures centered around controlled breathing (i.e. holding breath) are often ineffective for prolonged hiccups crises, but do have a significant efficacy for the most casual, short lasting cases. For these scenarios, the underlying rationale could be the displacement of an irritated nerve through prolonged diaphragmatic expansion.

However, one respiratory remedy has a fairly sound rationale underlying it. Breathing into a bag or small enclosed container (ensuring that it is completely sealed around the mouth and nose) induces a state of [[respiratory acidosis]]. The effect is caused by increasing the amount of inspired carbon dioxide, which then increases the level of carbon dioxide in the [[serum]]. These increased levels of CO2 lower the pH in the blood, hence creating a state of acidosis. This state of acidosis produces [[vasodilation]] and [[depression (physiology)|depression]] of the central nervous system. The effect allows for increased blood flow to the affected muscles, and suppression of the aberrant nervous impulses. Inducing a state of acidemia through hypoventilation is particularly effective in curing hiccups because the diaphragm rests directly against the pulmonary vasculature that is then flowing with especially low pH blood. This is a ''potentially dangerous'' action; and should only be done with another person present. As the serum CO2 level rises abruptly, the person will begin to feel lightheaded and within a few minutes will pass out. If done without a spotter, the person might either injure him or herself as he or she passes out, or pass out in such a way that the bag or container continues to prevent [[oxygen]] intake (see also [[asphyxia]]).

Another method is to simply run up and down a flight of stairs 3-4 times. This causes your breathing pattern to change which stops your hiccups. <ref>Christopher Siesky, Wadsworth City Schools</ref>

Additionally, another respiratory remedy appears to be one of the most effective in treating persistent hiccups. One breathes out all the air that he is able to in one long exhalation then breathes in all the air he feels he possibly can in one continuous inhalation. The person then attempts to breathe in even more air in a series of short powerful puffs, until his lungs cannot hold any more. The person remains in this state for as long as he feels a small gas bubble coming at the very base of the throat, ready to be burped. Although the success rate is not 100%, many people find this method consistently works. One scientific explanation for this method is that, by breathing an extreme load of air, the lungs tend to take more space in the chest, applying pressure on the surrounding content. The so-called gas bubble, which was located in an abnormal location potentially disturbing a nerve and causing the spasm, is then released.{{Fact|date=July 2007}}

====Psychosomatic====
* Distraction from one's hiccup (e.g. being startled, asked a perplexing question, or counting in reverse from 100 down or reciting the alphabet in reverse.){{Fact|date=June 2008}}
* Concentration on one's hiccups - using sheer will to stop them{{Fact|date=June 2008}}
* Pinch your ear lobe and breathe normally. Can turn into second-nature.{{Fact|date=June 2008}}

====Respiratory====
* Cutting air off from the esophagus. One method is to tip one's head forward and downward as far as possible.{{Fact|date=June 2008}}
* Isometric breathing, the process of breathing slowly and deeply in while thinking 'breathing out' and breathing slowly and fully out while thinking 'breathing in'{{Fact|date=June 2008}}
* Holding one's breath while optionally squeezing one's stomach.{{Fact|date=June 2008}}
* Breathing deeply through the nose, then exhaling slowly through the mouth. This is also a [[Lamaze]] technique.{{Fact|date=June 2008}}
* Exhaling all the air from one's lungs and holding one's breath while swallowing water or saliva.{{Fact|date=June 2008}}
* Blowing up a balloon{{Fact|date=June 2008}}
* Inducing [[sneezing]]{{Fact|date=June 2008}}
* Insert fingers in ears and hold breath for as long as possible{{Fact|date=June 2008}}
* Attempting to [[burp]]{{Fact|date=June 2008}}
* Exhaling all the air of one's lungs (or as much as possible, due to [[residual volume]]) and holding it as long as possible (theoretically stops the spasm on the diaphragm).{{Fact|date=June 2008}}

====Other====
* Eating something very sweet, or tart (particularly lemon juice), or both.<ref>{{cite web
| title = Hiccups
| publisher = Health911.com
| url = http://www.health911.com/remedies/rem_hic.htm
| accessdate = 2008-04-24}}</ref>
* Make out with someone. The sucking action during deep kisses stops the hiccups.{{Fact|date=June 2008}}
* Take a gulp of water or liquid, hold in mouth, insert fingers in ears and swallow while fingers are still in ears.{{Fact|date=June 2008}}
* In babies, hiccups are usually immediately stopped by the [[suckling reflex]], either by [[breastfeeding]] or simply by insertion of a finger, bottle teat or dummy into the baby's mouth.{{Fact|date=June 2008}}
* Close your eyes and look up as far as possible.{{Fact|date=June 2008}}
* Drinking a good amount of water{{Fact|date=June 2008}}
* Chew a spoonful of peanut butter slowly, or put sugar on the tongue.{{Fact|date=June 2008}}
* Mix sugar into a cup of water and drink slowly{{Fact|date=June 2008}}
* Press tongue hard against roof of mouth.{{Fact|date=June 2008}}
* Digital rectal massage<ref>{{cite journal
| last = Odeh
| first = M
| last2 = Bassan
| first2 = H
| last3 = Oliven
| first3 = A
| title = Termination of intractable hiccups with digital rectal massage
| journal = J Intern Med
| volume = 227
| issue = 2
| pages = 145-6
| publisher =
| location =
| date = 1990 February
| url = http://www.ncbi.nlm.nih.gov/pubmed/2299306?dopt=Abstract
| accessdate = 2008-04-24}}</ref>
* Drinking water from the back of a glass
* Get a bowl of water, fill it up, and stick your head in it. Breathe in deeply before you do this, and while in the bowl breathe out as SLOWLY as possible!{{Fact|date=June 2008}}
* Drink a glass of water through a paper towel.{{Fact|date=June 2008}}
* Bend over, drink a glass of water upside down while standing on one foot with one finger of your dominant in the opposite ear.{{Fact|date=June 2008}}
* Holding a spoon to your lips, slowly pour water over the spoon into your mouth and drink until hiccups subside.
* Or, if you're drunk, just hurl!{{Fact|date=June 2008}}

==Long-term cases==
American man [[Charles Osborne]] had the hiccups for 68 years, from 1922 to 1990, and was entered in the [[Guinness World Records]] as the man with the Longest Attack of Hiccups.<ref>"Survivor of 68-Year Hiccup Spell Dies.'' Omaha World - Herald, 05 May 1991, Sunrise Edition: 2.B.</ref>

In January 2007, teenager Jennifer Mee from [[Florida]] in the [[United States]] hiccuped for five weeks, from January 23, 2007 until February 28, 2007.<ref>{{cite news | url=http://www.msnbc.msn.com/id/17643118 | title=Florida girl hiccuping again after returning to school | date= [[March 16]], [[2007]] | publisher=msnbc.msn.com}}</ref> After her hiccups returned, however, her neurologist suggested that she may actually be suffering from [[Tourette Syndrome]].<ref>{{cite news | url=http://www.tampabays10.com/news/local/article.aspx?storyid=71545 | title=Hiccup Girl: "I have Tourette's" | date= [[January 10]], [[2008]] | publisher=WTSP-TV, tampabays10.com}}</ref>

==See also==
*[[Getting the wind knocked out of you]]

==References==
{{Reflist|2}}
* "Fish Out of Water", Neil Shubin, ''Natural History'', February 2008 issue, pages 26-31 - hiccup related to reflex in fish and amphibians.

==External links==
* [http://www.healthbasis.com/ie_content/health%20illustrated%20encyclopedia/1/003068.htm Hiccups - Considerations, Causes and Home Care (Healthbasis.com)]
* [http://my.webmd.com/hw/health_guide_atoz/ut1404.asp Hiccups (WebMD)]
* [http://www.straightdope.com/classics/a5_118.html The Straight Dope: What are hiccups and why do we get them?]
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2299306&dopt=Abstract Termination of intractable hiccups with digital rectal massage.]
* [http://www.musanim.com/mam/hiccup.htm Cures for Hiccups]
* [http://news.bbc.co.uk/2/hi/health/2730251.stm BBC News:Why we hiccup]
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12078929&dopt=Citation Retrospective analysis of hiccups in patients at a community hospital from 1995-2000.]

{{Circulatory and respiratory system symptoms and signs}}

[[Category:Symptoms]]

[[ca:Singlot]]
[[da:Hikke]]
[[de:Schluckauf]]
[[es:Hipo]]
[[eu:Zotin]]
[[fr:Hoquet]]
[[ko:딸꾹질]]
[[id:Cegukan]]
[[it:Singhiozzo]]
[[he:שיהוק]]
[[lb:Hick]]
[[lt:Žagsėjimas]]
[[hu:Csuklás]]
[[nl:Hik]]
[[ja:しゃっくり]]
[[no:Hikke]]
[[pl:Czkawka]]
[[pt:Soluço]]
[[qu:Hik'i]]
[[ru:Икота]]
[[scn:Sugghiuzzu]]
[[fi:Hikka]]
[[sv:Hicka]]
[[tr:Hıçkırık]]
[[yi:היקאפ]]
[[zh:打嗝]]

Brodmann area

2008-06-03T22:40:59Z

PhineasG: Undid revision 216808762 by 143.167.2.191 (talk)

[[Image:Gray726-Brodman.png|thumb|right|350px|Lateral surface of the brain with Brodmann's areas numbered.]]
[[Image:Gray727-Brodman.png|thumb|right|350px|Medial surface of the brain with Brodmann's areas numbered.]]
A '''Brodmann area''' is a region of the [[cerebral cortex|cortex]] defined based on its [[cytoarchitecture]], or organization of cells.

Brodmann areas were originally defined and numbered by '''[[Korbinian Brodmann]]''' based on the organization of [[neuron]]s he observed in the cortex using the [[Franz Nissl|Nissl]] [[staining|stain]]. Brodmann published his maps of cortical areas in humans, monkeys, and other species in 1909, along with many other findings and observations regarding the general cell types and [[Cerebral cortex#Laminar pattern|laminar organization]] of the mammalian cortex. (The same Brodmann area number in different species does not necessarily indicate homologous areas.) Although the Brodmann areas have been discussed, debated, refined, and renamed exhaustively for nearly a century, they remain the most widely known and frequently cited cytoarchitectural organization of the human cortex. Many of the areas Brodmann defined based solely on their neuronal organization have since been correlated closely to diverse cortical functions. For example, Brodmann's areas 1, 2 and 3 are the [[primary somatosensory cortex]]; area 4 is the [[primary motor cortex]]; area 17 is the [[primary visual cortex]]; and areas 41 and 42 correspond closely to [[primary auditory cortex]]. Higher order functions of the [[Cerebral cortex#association areas|association cortical areas]] are also consistently localized to the same Brodmann areas by [[neurophysiology|neurophysiological]], [[Functional magnetic resonance imaging|functional imaging]], and other methods (e.g., the consistent localization of [[Broca's area|Broca's]] speech and language area to the left Brodmann areas 44 and 45).

Some of the original Brodmann areas have been subdivided further, e.g., "23a" and "23b".<ref>{{Cite journal
| author = [[Brent A. Vogt]], [[Deepak N. Pandya]], Douglas L. Rosene
| title = Cingulate cortex of the rhesus monkey: I. Cytoarchitecture and thalamic afferents
| journal = [[The Journal of Comparative Neurology]]
| volume = 262
| issue = 2
| pages = 256–270
| month = August
| year = 1987
| doi = 10.1002/cne.902620207
}}</ref>

==Brodmann areas for human & non-human primates ==
* [[Brodmann areas 3, 1 and 2|Areas 1, 2 & 3 - Primary Somatosensory Cortex]] (frequently referred to as Areas 3, 1, 2 by convention)
* [[Brodmann area 4|Area 4 - Primary Motor Cortex]]
* [[Brodmann area 5|Area 5 - Somatosensory Association Cortex]]
* [[Brodmann area 6|Area 6]] - Pre-Motor and Supplementary Motor Cortex (Secondary Motor Cortex)
* [[Brodmann area 7|Area 7 - Somatosensory Association Cortex]]
* [[Brodmann area 8|Area 8]] - Includes [[Frontal eye fields]]
* [[Brodmann area 9|Area 9]] - [[Dorsolateral prefrontal cortex]]
* [[Brodmann area 10|Area 10]] - [[Anterior prefrontal cortex]] (most rostral part of superior and middle frontal gyri)
* [[Brodmann area 11|Area 11]] - [[Orbitofrontal cortex|Orbitofrontal area]] (orbital and rectus gyri, plus part of the rostral part of the superior frontal gyrus)
* [[Brodmann area 12|Area 12]] - [[Orbitofrontal cortex|Orbitofrontal area]] (used to be part of BA11, refers to the area between the superior frontal gyrus and the inferior rostral sulcus)
* [[Brodmann area 13|Area 13]] and [[Brodmann area 14|Area 14]]* - [[Insular cortex]]
* [[Brodmann area 15|Area 15]]* - Anterior Temporal Lobe
* [[Brodmann area 17|Area 17]] - [[Visual_cortex#V1|Primary visual cortex (V1)]]
* [[Brodmann area 18|Area 18]] - [[Visual_cortex#V2|Secondary visual cortex (V2)]]
* [[Brodmann area 19|Area 19]] - [[Visual_cortex#V3|Associative visual cortex (V3)]]
* [[Brodmann area 20|Area 20]] - [[Inferior temporal gyrus]]
* [[Brodmann area 21|Area 21]] - [[Middle temporal gyrus]]
* [[Brodmann area 22|Area 22]] - [[Superior temporal gyrus]], of which the caudal part participates to [[Wernicke's area]]
* [[Brodmann area 23|Area 23]] - Ventral [[Posterior cingulate cortex]]
* [[Brodmann area 24|Area 24]] - Ventral [[Anterior cingulate cortex]]
* [[Brodmann area 25|Area 25]] - [[Subgenual cortex]]
* [[Brodmann area 26|Area 26]] - [[Ectosplenial area]]
* [[Brodmann area 27|Area 27]] - [[piriform area]]
* [[Brodmann area 28|Area 28]] - Posterior [[Entorhinal Cortex]]
* [[Brodmann area 29|Area 29]] - Retrosplenial [[cingular cortex]]
* [[Brodmann area 30|Area 30]] - Part of [[cingular cortex]]
* [[Brodmann area 31|Area 31]] - Dorsal [[Posterior cingular cortex]]
* [[Brodmann area 32|Area 32]] - Dorsal [[anterior cingulate cortex]]
* [[Brodmann area 33|Area 33]] - Part of [[anterior cingulate cortex]]
* [[Brodmann area 34|Area 34]] - Anterior [[Entorhinal Cortex]] (on the [[Parahippocampal gyrus]])
* [[Brodmann area 35|Area 35]] - [[Perirhinal cortex]] (on the [[Parahippocampal gyrus]])
* [[Brodmann area 36|Area 36]] - [[Parahippocampal cortex]] (on the [[Parahippocampal gyrus]])
* [[Brodmann area 37|Area 37]] - [[Fusiform gyrus]]
* [[Brodmann area 38|Area 38]] - Temporopolar area (most rostral part of the superior and middle temporal gyri)
* [[Brodmann area 39|Area 39]] - [[Angular gyrus]], part of [[Wernicke's area]]
* [[Brodmann area 40|Area 40]] - [[Inferior parietal cortex|Supramarginal gyrus]] part of [[Wernicke's area]]
* [[Brodmann area 41 & 42|Areas 41 & 42 - Primary and Auditory Association Cortex]]
* [[Brodmann area 43|Area 43]] - Subcentral area (between insula and post/precentral gyrus)
* [[Brodmann area 44|Area 44]] - [[pars opercularis]], part of [[Broca's area]]
* [[Brodmann area 45|Area 45]] - [[pars triangularis]] [[Broca's area]]
* [[Brodmann area 46|Area 46]] - [[Dorsolateral prefrontal cortex]]
* [[Brodmann area 47|Area 47]] - Inferior prefrontal gyrus
* [[Brodmann area 48|Area 48]] - Retrosubicular area (a small part of the medial surface of the temporal lobe)
* [[Brodmann area 52|Area 52]] - Parainsular area (at the junction of the temporal lobe and the [[insula]])

(*) Area only found in non-human [[primate]]s.

== Criticism ==
When von Bonin and Bailey were to construct a brain map for the [[macaque]] monkey they found the description of Brodmann inadequate and wrote:
: ''Brodmann (1907), it is true, prepared a map of the human brain which has been widely reproduced, but, unfortunately, the data on which it was based was never published''<ref>{{Cite book
| author = Gerhardt von Bonin & Percival Bailey
| title = The Neocortex of Macaca Mulatta
| publisher = [[The University of Illinois Press]]
| location = [[Urbana]], [[Illinois]]
| year = [[1925]]
}}</ref>
They instead used the cytoarchitechtonic scheme of [[Constantin von Economo]] and [[Georg N. Koskinas]] published in 1925<ref>{{Cite book
| author = [[Constantin von Economo]] & [[Georg N. Koskinas]]
| title = Die Cytoarchitektonik der Hirnrinde des erwachsenen Menschen
| publisher = [[Julius Springer]]
| year = 1925
| location = Vienna and Berlin
}}</ref>
which had the "only acceptable detailed description of the human cortex".

== See also ==
* [[Brain]]
* [[Cortical area]]
* [[List of regions in the human brain]]

== References ==
{{Refimprove|date=November 2007}}
<div class="references-small">
<references/>
</div>

== External links ==
* [http://www.trincoll.edu/~dlloyd/brodmann.html brodmann x func] — Functional categorization of Brodmann areas.
* [http://spot.colorado.edu/~dubin/talks/brodmann/brodmann.html Brodmann], Mark Dubin pages on Brodmann areas.
* [http://braininfo.rprc.washington.edu/scripts/indexotheratlas.aspx?othersiteID= Brodmann areas of cortex involved in language]

{{Telencephalon}}
[[Category:Brodmann areas|*]]
[[Category:Cerebrum]]
[[Category:Neuroanatomy]]
[[Category:Cognitive neuroscience]]

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Cerebrum

2008-06-02T12:46:00Z

PhineasG: removed apoptosis section (see talk page). other minor edits

{{Infobox Brain|
Name = {{Telencephalon}} |
Latin = |
GraySubject = |
GrayPage = |
Map = Cerebrum map|
MapPos = |
MapCaption = The lobes of the cerebral cortex include the [[frontal lobe|frontal]] (blue), [[temporal lobe|temporal]] (green), [[occipital lobe|occipital]] (red), and [[parietal lobe]]s (yellow). The [[cerebellum]] (unlabeled) is not part of the telencephalon. |
Image2 = EmbryonicBrain.svg |
Caption2 = Diagram depicting the main subdivisions of the embryonic vertebrate brain. |
IsPartOf = |
Components = |
Artery = [[anterior cerebral artery|anterior cerebral]], [[middle cerebral artery|middle cerebral]], [[posterior cerebral artery|posterior cerebral]] |
Vein = [[cerebral veins]] |
BrainInfoType = |
BrainInfoNumber = |
MeshName = Telencephalon |
MeshNumber = A08.186.21.730.885 |
DorlandsPre = |
DorlandsSuf = |
}}
The '''telencephalon''' ({{pronEng|tɛlɛnˈsɛfəlɒn}}), '''cerebrum''', or '''forebrain''' is the most [[anterior]] or, especially in humans, most [[dorsal]] region of the [[vertebrate]] [[central nervous system]]. "Telencephalon" refers to the embryonic structure, from which the mature "cerebrum" develops. The [[dorsal]] telencephalon, or [[pallium]], develops into the [[cerebral cortex]], and the [[ventral]] telencephalon, or [[subpallium]], becomes the [[basal ganglia]]. The cerebrum is also divided into symmetric left and right cerebral hemispheres.

== Development ==
During vertebrate embryonic development, the [[prosencephalon]], the most anterior of three [[Vesicle (Biology)|vesicle]]s that form from the [[embryo]]nic [[neural tube]], is further subdivided into the telencephalon and [[diencephalon]]. The telencephalon then forms two lateral telencephalic vesicles which develop into the left and right cerebral hemispheres.

== Structure ==
The cerebrum is composed of the following sub-regions:
* [[Cerebral cortex]], or cortices of the cerebral hemispheres
* [[Basal ganglia]], or basal nuclei (also often called the striatum)
* [[Olfactory bulb]]

== Composition ==
The cerebrum comprises what most people think of as the "[[brain]]." It lies in front or on top of the [[brainstem]] and in humans is the largest and most well-developed of the five major divisions of the brain. The cerebrum is the newest structure in the [[phylogenetic]] sense, with [[mammal]]s having the largest and most well-developed among all [[species]]. In larger mammals, the cerebral cortex is folded into many gyri and sulci, which has allowed the cortex to expand in surface area without taking up much greater volume. '''See also''' [[Cerebral Cortex]].

In [[human]]s, the cerebrum surrounds older parts of the brain. Limbic, olfactory, and motor systems project fibers from the cerebrum to the [[brainstem]] and [[spinal cord]]. [[Cognition|Cognitive]] and [[volition (psychology)|volitive]] systems project fibers from the cerebrum to the [[thalamus]] and to specific regions of the [[midbrain]]. The neural networks of the cerebrum facilitate complex behaviors such as social interactions, learning, [[working memory]], and in humans, speech and [[language]].

== Functions ==
'''Note''': As the cerebrum is a gross division with many subdivisions and sub-regions, it is important to state that this section lists the functions that the cerebrum ''as a whole'' serves. See main articles on [[cerebral cortex]] and [[basal ganglia]] for more information.

=== Movement ===
The cerebrum directs the conscious or volitional motor functions of the body. These functions originate within the [[primary motor cortex]] and other frontal lobe motor areas where actions are planned. [[Upper motor neuron]]s in the primary motor cortex send their [[axon]]s to the brainstem and spinal cord to [[synapse]] on the [[lower motor neurons]], which innervate the muscles. Damage to motor areas of cortex can lead to certain types of [[motor neuron disease]]. This kind of damage results in loss of muscular power and precision rather than total [[paralysis]].

=== Sensory Processing ===
The primary sensory areas of the [[cerebral cortex]] receive and process visual, auditory, [[somatosensory]], [[gustatory]], and [[olfactory]] information. Together with association cortical areas, these brain regions synthesize sensory information into our perceptions of the world around us.

=== Olfaction ===
{{Main|Olfaction}}
The [[olfactory bulb]] in most vertebrates is the most anterior portion of the cerebrum, and makes up a relatively large proportion of the telencephalon. However, in humans, this part of the brain is much smaller, and lies underneath the frontal lobe. The olfactory sensory system is unique in the sense that neurons in the olfactory bulb send their axons directly to the [[piriform cortex|olfactory cortex]], rather than to the [[thalamus]] first. Damage to the olfactory bulb results in a loss of the sense of smell.

=== Language and communication ===
{{Main|Language}}
[[Speech communication|Speech]] and language are mainly attributed to parts of the cerebral cortex. Motor portions of language are attributed to [[Broca's area]] within the frontal lobe. Speech comprehension is attributed to [[Wernicke's area]], at the temporal-parietal lobe junction. These two regions are interconnected by a large white matter tract, the [[arcuate fasciculus]]. Damage to the Broca's area results in [[expressive aphasia]] (non-fluent aphasia) while damage to Wernicke's area results in [[receptive aphasia]] (also called fluent aphasia).

=== Learning and Memory ===
{{Main|Memory}}
Explicit or declarative (factual) memory formation is attributed to the [[hippocampus]] and associated regions of the medial temporal lobe. This association was originally described after a patient known as [[HM (patient)|HM]] had both his hippocampuses (left and right) surgically removed to treat severe epilepsy. After surgery, HM had [[anterograde amnesia]], or the inability to form new memories. This condition is also portrayed in the film ''[[Memento (film)|Memento]]'', in which the protagonist has to take pictures of people he has met in order to be able to remember what to do in the days following his accident.

Implicit or procedural memory, such as complex motor behaviors, involve the basal ganglia. Therefore,

== Cell regeneration ==
=== Xenopus laevis ===
==== Larval stage ====
In a study of the telencephalon conducted in [[Hokkaido University]] on [[African clawed frog]]s (''xenopus laevis''){{ref|Yoshino}}, it was discovered that, during [[larva]]l stages, the telencephalon was able to regenerate around half of the anterior portion (otherwise known as '''partially truncated'''), after a reconstruction of a would-be accident, or malformation of features.

The regeneration and active proliferation of cells within the clawed frog is quite remarkable, regenerated cells being almost functionally identical to the ones originally found in the brain after birth, despite the lack of brain matter for a sustained period of time.

This kind of regeneration depends on ependymal layer cells covering the cerebral lateral ventricles, within a short period before, or within the initial stage of wound-healing. This is observed within the stages of healing within larvae of the clawed frog.

==== Developed stage ====
The regeneration within the developed stage of the clawed frog is different from that in the larval stage. Because the cells adhere to one another, they are unable to form an entity that can cover the cerebral lateral ventricles. Thus, the telencephalon remains truncated and the loss of function becomes permanent.

==== Effects of abnormality ====
After removing over half of the telencephalon in the developed stage of the clawed frog, the lack of functions within the animal was apparent, manifesting with obvious difficulties in movement, [[nonverbal communication]] between other species, as well as other difficulties thought to be similar to those seen in humans.

This kind of regeneration is still relatively unknown in regard to regeneration within larval stages, similar to the human [[fetus|fetal stage]].

== References ==
#{{note|Levi-Oppenheim}} Levi-Montalcini, R. (1949) Proliferation, differentiation and degeneration in the spinal ganglia of the chick embryo under normal and experimental conditions. Pages 450 - 502
#{{note|Yoshino}} Yoshino J, Tochinai S. Successful reconstitution of the non-regenerating adult telencephalon by cell transplantation in Xenopus laevis. ''Dev Growth Differ.'' 2004;46(6):523–34. PMID 15610142
#{{note|Yaginuma}} Yaginuma, H., Tomita, M., Takashita, N., McKay, S., Cardwell, C., Yin, Q.- Aminobuytric acid immunoreactivity within the human cerebral cortex. Pages 481 - 500
#{{note|Haydar}} Haydar, T. F, Kuan, C., Y., Flavell, R. A. & Rakic, P. (1999) The role of cell death in regulating the size and shape of the mammalian forebrain. Pages 621 - 626

== See also==
* [[List of regions in the human brain]]
* [[Cerebral cortex]]
* [[Basal ganglia]]

==External links==
*[http://www.rahulgladwin.com/blog/2006/06/cerebrum-higher-integrative-functions.html Cerebrum Medical Notes on rahulgladwin.com]

{{Prosencephalon}}

[[Category:Neuroanatomy]]
[[Category:Cerebrum]]
[[Category:Central nervous system]]
[[Category:Cranial nerves]]
[[Category:Developmental biology]]

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[[ja:大脳]]
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Functional magnetic resonance imaging

2008-05-28T00:57:35Z

PhineasG: /* Is fMRI worthwhile? */

'''Functional [[magnetic resonance imaging]] (fMRI)''' measures the [[haemodynamic response]] related to [[neuron|neural]] activity in the [[brain]] or [[spinal cord]] of [[human]]s or other animals. It is one of the most recently developed forms of [[neuroimaging]].

[[Image:FMRI.jpg|thumb|250px|right|fMRI data (yellow) overlaid on an average of the brain anatomies of several humans (gray)]]

== Background ==

Since the 1890s (Roy and [[Charles Scott Sherrington|Sherrington]], 1890) it has been known that changes in [[blood flow]] and blood oxygenation in the [[brain]] (collectively known as [[hemodynamics]]) are closely linked to neural activity. When nerve cells are active they consume [[oxygen]] carried by [[hemoglobin]] in [[red blood cells]] from local [[capillary|capillaries]]. The local response to this oxygen utilization is an increase in blood flow to regions of increased neural activity, occurring after a delay of approximately 1-5 seconds. This hemodynamic response rises to a peak over 4-5 seconds, before falling back to baseline (and typically undershooting slightly). This leads to local changes in the relative concentration of oxyhemoglobin and deoxyhemoglobin and changes in local cerebral [[blood volume]] in addition to this change in local [[cerebral blood flow]].

'''Blood-oxygen-level dependent''' or BOLD fMRI is a method of observing which areas of the [[brain]] are active at any given time. It was found by Dr. [[Seiji Ogawa]]<ref>Ogawa, S., Lee, T.M., Nayak, A.S., and Glynn, P. (1990). Oxygenation-sensitive contrast in magnetic resonance image of rodent brain at high magnetic fields. Magn Reson Med 14, 68-78 </ref> and Dr. [[Robert Turner (Scientist)|Robert Turner]], working independently, in 1990. [[Neurons]] do not have internal reserves of energy in the form of [[sugar]] and [[oxygen]], so their firing causes a need for more energy to be brought in quickly. Through a process called the [[hemodynamic response]], blood releases oxygen to them at a greater rate than to inactive neurons, and the difference in [[magnetic susceptibility]] between oxyhemoglobin and [[Hemoglobin|deoxyhemoglobin]], and thus oxygenated or deoxygenated [[blood]], leads to magnetic signal variation which can be detected using an MRI scanner. Given many repetitions of a thought, action or experience, statistical methods can be used to determine the areas of the brain which reliably have more of this difference as a result, and therefore which areas of the brain are active during that thought, action or experience.

Almost all fMRI research uses BOLD as the method for determining where activity occurs in the brain as the result of various experiences, but because the signals are relative, and not individually quantitative, some question its rigor. Other methods which propose to measure neural activity directly have been attempted (for example, measurement of the Oxygen Extraction Fraction, or OEF, in regions of the brain, which measures how much of the oxyhemoglobin in the blood has been converted to deoxyhemoglobin<ref>[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&list_uids=7869897&dopt=Citation Theory of NMR signal behavior in magnetically inho...[Magn Reson Med. 1994] - PubMed Result]</ref>), but because the electromagnetic fields created by an active or firing neuron are so weak, the [[signal-to-noise ratio]] is extremely low and [[Statistics|statistical]] methods used to extract quantitative data have been largely unsuccessful as of yet.

[[Hemoglobin]] is [[diamagnetic]] when oxygenated but [[paramagnetic]] when deoxygenated. The [[magnetic resonance]] (MR) signal of blood is therefore slightly different depending on the level of oxygenation. These differential signals can be detected using an appropriate MR pulse sequence as [[blood-oxygen-level dependent]] (BOLD) contrast. Higher BOLD signal intensities arise from increases in the concentration of oxygenated [[hemoglobin]] since the blood [[magnetic susceptibility]] now more closely matches the tissue magnetic susceptibility. By collecting data in an [[MRI]] scanner with parameters sensitive to changes in magnetic susceptibility one can assess changes in BOLD contrast. These changes can be either positive or negative depending upon the relative changes in both cerebral blood flow (CBF) and oxygen consumption. Increases in CBF that outstrip changes in oxygen consumption will lead to increased BOLD signal, conversely decreases in CBF that outstrip changes in oxygen consumption will cause decreased BOLD signal intensity.

==Neural correlates of BOLD==
The precise relationship between neural signals and BOLD is under active research. In general, changes in BOLD signal are well correlated with changes in blood flow. Numerous studies during the past several decades have identified a coupling between blood flow and [[Metabolism|metabolic rate]]; that is, the blood supply is tightly regulated in space and time to provide the nutrients for brain metabolism. However, [[neuroscience|neuroscientists]] have been seeking a more direct relationship between the blood supply and the neural inputs/outputs that can be related to observable electrical activity and circuit models of brain function.

While current data indicate that [[local field potential]]s, an index of integrated electrical activity, form a marginally better correlation with blood flow than the spiking [[action potential]]s that are most directly associated with neural communication, no simple measure of electrical activity to date has provided an adequate correlation with metabolism and the blood supply across a wide dynamic range. Presumably, this reflects the complex nature of metabolic processes, which form a superset with regards to electrical activity. Some recent results have suggested that the increase in cerebral blood flow (CBF) following neural activity is not causally related to the metabolic demands of the brain region, but rather is driven by the presence of [[neurotransmitter]]s, especially [[Glutamic acid|glutamate]].

Some other recent results suggest that an initial small, negative dip before the main positive BOLD signal is more highly localized and also correlates with measured local decreases in tissue oxygen concentration (perhaps reflecting increased local [[metabolism]] during neuron activation). Use of this more localized negative BOLD signal has enabled imaging of human [[ocular dominance columns]] in [[Visual cortex|primary visual cortex]], with resolution of about 0.5 mm. One problem with this technique is that the early negative BOLD signal is small and can only be seen using larger scanners with magnetic fields of at least 3 [[Tesla (unit)|Tesla]]. Further, the signal is much smaller than the normal BOLD signal, making extraction of the signal from noise that much more difficult. Also, this initial dip occurs within 1-2 seconds of stimulus initiation, which may not be captured when signals are recorded at long repetition (TR). If the TR is sufficiently low, increased speed of the cerebral blood flow response due to consumption of vasoactive drugs (such as caffeine<ref>{{cite journal
| author=Behzadi, Y. ''et al''
| title=Caffeine reduces the initial dip in the visual bold response at 3 t.
| journal=Neuroimage
| year=2006
| volume=32
| pages=9-15
| doi=10.1016/j.neuroimage.2006.03.005
}}
</ref>) or natural differences in vascular responsivnesses may further obscure observation of the initial dip.

The BOLD signal is composed of CBF contributions from larger arteries and veins, smaller arterioles and venules, and capillaries. Experimental results indicate that the BOLD signal can be weighted to the smaller vessels, and hence closer to the active neurons, by using larger magnetic fields. For example, whereas about 70% of the BOLD signal arises from larger vessels in a 1.5 tesla scanner, about 70% arises from smaller vessels in a 4 tesla scanner. Furthermore, the size of the BOLD signal increases roughly as the square of the magnetic field strength. Hence there has been a push for larger field scanners to both improve localization and increase the signal. A few 7 tesla commercial scanners have become operational, and experimental 8 and 9 tesla scanners are under development.

[[Image:brain chrischan.jpg|thumb|250px|right|A sagittal slice of a Structural [[MRI]] scan of a human head. The nose is to the left.[[:Image:brain chrischan 300.gif|Click here]] to view an animated sequence of slices.]]

[[Image:User-FastFission-brain-frame44.png|thumb|250px|right|A slice of an [[MRI]] scan of the brain. The forehead is at the top and the back of the head is at the bottom. [[:Image:User-FastFission-brain.gif|Click here]] to view an animation of the scan from top to bottom.]]

== Technique ==

BOLD effects are measured using rapid volumetric acquisition of images with contrast weighed by T2 or T2* (see [[MRI]]). Such images can be acquired with moderately good spatial and temporal resolution; images are usually taken every 1–4 seconds, and the [[voxel]]s in the resulting image typically represent cubes of tissue about 2–4 millimeters on each side in humans. Recent technical advancements, such as the use of high magnetic fields and advanced "multichannel" RF reception, have advanced spatial resolution to the millimeter scale. Although responses to stimuli presented as close together as one or two seconds can be distinguished from one another, using a method known as event-related fMRI, the full time course of a BOLD response to a briefly presented stimulus lasts about 15 seconds for the robust positive response.

== fMRI studies draw from many disciplines ==

To use fMRI effectively, an investigator must have a firm grasp of the relevant principles from all of these fields:

* [[Physics]]: Researchers should have a reasonable understanding of the physical principles underlying fMRI.
* [[Psychology]]: Almost all fMRI studies are essentially [[cognitive psychology|cognitive psychological]], [[physiological psychology|cognitive psychophysiological]], and/or [[psychophysics|psychophysical]] experiments in which the MRI scanner is used to obtain an extra set of measurements in addition to behavioral and [[electroencephalographic]] measurements. This allows for more detailed theory testing and inference on perceptual and cognitive processes, and allows to relate these to specific brain structures.
* [[Neuroanatomy]]: The fMRI signals can be put into the context of previous knowledge only with an understanding of the neuroanatomy. Ultimately, the goal of all functional imaging experiments is to explain [[human cognition]] and behavior in terms of physical (anatomical) mechanisms.
* [[Statistics]]: Correct application of statistics is essential to "tease out" observations and avoid [[Type I and type II errors|false-positive]] results.
* [[Electrophysiology]]: Familiarity with neuronal behavior at the electrophysiological level can help investigators design a useful fMRI study.

[[Seiji Ogawa]] and [[Kenneth Kwong]] are generally credited as the discoverers of the BOLD effect that underlies conventional fMRI.

==Advantages and Disadvantages of fMRI==
Like any technique, fMRI has advantages and disadvantages, and in order to be useful, the experiments that employ it must be carefully designed and conducted to maximize its strengths and minimize its weaknesses.

===General disadvantages of the method===

* The BOLD signal is only an indirect measure of neural activity, and is therefore susceptible to influence by non-neural changes in the body.

* BOLD signals are most strongly associated with the input to a given area than with the output. It is therefore possible (although unlikely) that a BOLD signal could be present in a given area even if there is no single unit activity.<ref>{{cite journal
| author=Logothetis, N.K.
| year=2001
| title=Neurophysiological investigation of the basis of the fMRI signal.
| journal=Nature
| volume=412
| url=http://www.ssc.uwo.ca/psychology/culhamlab/fmri/pdfs/Logothetis.pdf

| pages=150

| doi=10.1038/35084005
}}</ref>

* Different brain areas have different hemodynamic responses, which would not be accurately reflected by the [[general linear model]] often used to filter fMRI time signals.

* For a non-invasive scan, fMRI has moderately good spatial resolution. However, the temporal response of the blood supply, which is the basis of fMRI, is poor relative to the electrical signals that define neuronal communication. Therefore, some research groups are working around this issue by combining fMRI with data collection techniques such as [[electroencephalography]] (EEG) or [[magnetoencephalography]] (MEG). EEG has much higher temporal resolution but rather poor spatial resolution, whereas MEG has much higher temporal resolution and similar spatial resolution. This has led some to suggest MEG is a more valuable tool than fMRI.

* fMRI has often been used to show activation localized to specific regions, thus minimizing the distributed nature of processing in [[Biological neural network|neural networks]]. Several recent [[multivariate]] statistical techniques work around this issue by characterizing interactions between "active" regions found via traditional [[univariate]] techniques. Such techniques might prove useful in the future.

* fMRI is usually used to try to determine "where" task-related activity occurs in the brain. This has led to the charge that it is simply a modern-day phrenology.{{fact}} Some scientists prefer models which explain "how" psychological mechanisms function. The counter-argument to this criticism is that knowing "where" a cognitive function is located is vitally important. [[Neuropsychology]], [[neurophysiology]], and [[functional imaging]] each give us different windows of understanding into what each brain region does and how. The analogy to phrenology is somewhat misleading: [[phrenology]] has little or no basis in the [[scientific method]], whereas fMRI permits hypotheses to be tested and strong inferences to be made.

* Many theoretical models used to explain fMRI signals are so poorly specified that they are not [[Falsifiability|falsifiable]] (a central tenet from the [[scientific method]]). Hence, some argue, fMRI is not really a "science."{{fact}} The counter-argument is that an fMRI study can provide evidence to falsify a prior theory if it is well-designed. Also, well-specified mathematical and computational models of the neural processes underlying fMRI can make theories more concrete, allowing them to make predictions that can be verified or falsified by fMRI.

===Advantages of fMRI===

* It can noninvasively record brain signals (of humans and other animals) without risks of radiation inherent in other scanning methods, such as [[Computed tomography|CT]] scans.
* It can record on a spatial resolution in the region of 3-6 millimeters, but with relatively poor temporal resolution (on the order of seconds) compared with techniques such as EEG. However, this is mainly because of the phenomena being measured, not because of the technique. EEG measures electrical/neural activity while fMRI measures blood activity, which has a longer response. The MRI equipment used for fMRI can be used for high temporal resolution, if one measures different phenomena.

===General counterargument===

Like any other technique, fMRI is as worthwhile as the design of the experiment using it. Many investigators have used fMRI ineffectively because they were not familiar with all aspects of the technique, or because they received their academic training in disciplines characterized by less rigor than some other branches of psychology and neuroscience. Ineffective use of the technique is a problem for the field, but it is not a consequence of the technique itself.

While the mechanistic information provided by fMRI is limited relative to classical techniques of electrophysiology and molecular biology, this is a general criticism of systems-level biology based upon changes in metabolism, blood supply, or ensemble indices of electrical activity. Most researchers believe that both "bottom-up" and "top-down" measurements are needed to inform our understanding of the complex mechanisms that transpose neural activity into behavior.

=== Commercial use ===
''Omneuron'' [http://www.omneuron.com/] is a US-based company founded by [[Christopher deCharms]] that is researching potential practical and clinical applications of real time fMRI.

''Applied fMRI Institute'' [http://www.appliedfmri.org] is a [[San Diego, CA]] based company offering commercial use of their [[Siemens]] 3T TIM Trio.

''Neurognostics'' [http://www.neurognostics.com/] is a US-based company that offers a standardized fMRI system

''Imagilys'' [http://www.imagilys.com/] is a European company specialized in clinical and research fMRI.

At least two companies have been set up to use fMRI in [[lie detection]]. They are ''No Lie MRI, Inc'' [http://www.noliemri.com/] and ''Cephos Corporation'' [http://www.cephoscorp.com/]. In episode 109 of the popular science show [[Mythbusters]], the three members of the build team attempted to fool an FMRI test. Although two of them were unsuccessful, the third was able to successfully fool the machine.

The signals are extrapolated from the fMRI machine onto a screen, displaying the active regions of the brain. Depending on what regions are the most active, the technician can determine whether a subject is telling the truth or not. This technology is in its early stages of development, and many of its proponents hope to replace older lie detection techniques.

== Scanning in practice ==

[[Image:Varian4T.jpg|thumb|250px|right|[[University of California, Berkeley|Berkeley's]] 4T fMRI scanner.]]
Subjects participating in a fMRI experiment are asked to lie still and are usually restrained with soft pads to prevent small motions from disturbing measurements. Some labs also employ bite bars to reduce motion, although these are unpopular as they can cause some discomfort to subjects. It is possible to correct for some amount of head movement with post-processing of the data, but large transient motion can render these attempts futile. Generally motion in excess of 3 millimeters will result in unusable data. The issue of motion is present for all populations, but most notably within populations that are not physically or emotionally equipped for even short MRI sessions (e.g., those with [[Alzheimer's Disease]] or [[schizophrenia]], or young children). In these populations, various and negative [[reinforcement]] strategies can be employed in an attempt to attenuate motion artifacts, but in general the solution lies in designing a compatible paradigm with these populations.

An fMRI experiment usually lasts between 15 minutes and 2 hours. Depending on the purpose of study, subjects may view movies, hear sounds, smell odors, perform cognitive tasks such as memorization or imagination, press a few buttons, or perform other tasks. Researchers are required to give detailed instructions and descriptions of the experiment plan to each subject, who must sign a consent form before the experiment.

Safety is a very important issue in all experiments involving MRI. Potential subjects must ensure that they are able to enter the MRI environment. Due to the nature of the MRI scanner, there is an extremely strong magnetic field surrounding the MRI scanner (at least 1.5 [[tesla (unit)|teslas]], possibly stronger). Potential subjects must be thoroughly examined for any ferromagnetic objects (e.g. watches, glasses, hair pins, pacemakers, bone plates and screws, etc.) before entering the scanning environment.

== Related techniques ==

Aside from fMRI, there are other related ways to probe brain activity using magnetic resonance properties:

===Contrast MR===
An injected [[Radiocontrast|contrast agent]] such as an [[iron oxide]] that has been coated by a [[sugar]] or [[starch]] (to hide from the body's defense system), causes a local disturbance in the [[magnetic field]] that is measurable by the MRI scanner. The signals associated with these kinds of contrast agents are proportional to the cerebral blood volume. While this semi-invasive method presents a considerable disadvantage in terms of studying brain function in normal subjects, it enables far greater detection sensitivity than BOLD signal, which may increase the viability of fMRI in clinical populations. Other methods of investigating blood volume that do not require an injection are a subject of current research, although no alternative technique in theory can match the high sensitivity provided by injection of contrast agent.

===Arterial spin labeling===
By magnetic labeling the proximal blood supply using "arterial spin labeling" ASL, the associated signal is proportional to the cerebral blood flow, or [[perfusion]]. This method provides more quantitative physiological information than BOLD signal, and has the same sensitivity for detecting task-induced changes in local brain function

===Magnetic resonance spectroscopic imaging===
Magnetic resonance spectroscopic imaging (MRS) is another, [[Nuclear magnetic resonance|NMR]]-based process for assessing function within the living brain. MRS takes advantage of the fact that [[proton]]s ([[hydrogen]] atoms) residing in differing chemical environments depending upon the molecule they inhabit (H2O vs. [[protein]], for example) possess slightly different resonant properties. For a given volume of brain (typically > 1 cubic cm), the distribution of these H resonances can be displayed as a [[spectroscopy|spectrum]].

The area under the peak for each resonance provides a quantitative measure of the relative abundance of that compound. The largest peak is composed of H2O. However, there are also discernible peaks for [[choline]], [[creatine]], [[N-Acetylaspartate|''N''-acetylaspartate]] (NAA) and [[lactic acid|lactate]]. Fortuitously, NAA is mostly inactive within the neuron, serving as a precursor to glutamate and as storage for acetyl groups (to be used in [[fatty acid]] synthesis) — but its relative levels are a reasonable approximation of neuronal integrity and functional status. Brain diseases ([[schizophrenia]], [[stroke]], certain [[tumor]]s, [[multiple sclerosis]]) can be characterized by the regional alteration in NAA levels when compared to healthy subjects. Creatine is used as a relative control value since its levels remain fairly constant, while choline and lactate levels have been used to evaluate [[brain tumor]]s.

===Diffusion tensor imaging===
[[Diffusion tensor imaging]] (DTI) is a related use of MR to measure anatomical connectivity between areas. Although it is not strictly a functional imaging technique because it does not measure dynamic changes in brain function, the measures of inter-area connectivity it provides are complementary to images of [[cerebral cortex|cortical]] function provided by BOLD fMRI. [[White matter]] bundles carry functional information between brain regions. The diffusion of water molecules is hindered across the axes of these bundles, such that measurements of water diffusion can reveal information about the location of large white matter pathways. Illnesses that disrupt the normal organization or integrity of cerebral white matter (such as multiple sclerosis) have a quantitative impact on DTI measures.

== Approaches to fMRI data analysis ==

The ultimate goal of fMRI data analysis is to detect correlations between brain activation and the task the subject performs during the scan. The BOLD signature of activation is relatively weak, however, so other sources of noise in the acquired data must be carefully controlled. This means that a series of processing steps must be performed on the acquired images before the actual statistical search for task-related activation can begin.

For a typical fMRI scan, the 3D volume of the subject's head is imaged every one or two seconds, producing a few hundred to a few thousand complete images per scanning session. The nature of MRI is such that these images are acquired in [[Fourier transform]] space, so they must be transformed back to image space to be useful. Because of practical limitations of the scanner the Fourier samples are not acquired on a grid, and scanner imperfections like thermal drift and spike noise introduce additional distortions. Small motions on the part of the subject and the subject's pulse and respiration will also affect the images.

The most common situation is that the researcher uses a [[mri#resonance and relaxation|pulse sequence]] supplied by the scanner vendor, such as an [[mri|imaging|echo-planar imaging (EPI)]] sequence that allows for relatively rapid acquisition of many images. Software in the scanner platform itself then performs the reconstruction of images from Fourier transform space. During this stage some information is lost (specifically the complex phase of the reconstructed signal). Some types of artifacts, for example spike noise, become more difficult to remove after reconstruction, but if the scanner is working well these artifacts are thought to be relatively unimportant. For pulse sequences not provided by the vendor, for example spiral EPI, reconstruction must be done by software running on a separate platform.

After reconstruction the output of the scanning session consists of a series of 3D images of the brain. The most common corrections performed on these images are motion correction and correction for physiological effects. Outlier correction and spatial and/or temporal filtering may also be performed. If the task performed by the subject is thought to produce bursts of activation which are short compared to the BOLD response time (on the order of 6 seconds), temporal filtering may be performed at this stage to attempt to [[deconvolution|deconvolve]] out the [[BOLD]] response and recover the temporal pattern of activation.

At this point the data provides a time series of samples for each voxel in the scanned volume. A variety of methods are used to correlate these voxel time series with the task in order to produce maps of task-dependent activation.

Some fMRI [[neuroimaging software]]:
* [[Analysis of Functional NeuroImages|AFNI]] [http://afni.nimh.nih.gov]
* [[BrainVoyager]] [http://www.brainvoyager.com]
* [[Cambridge Brain Analysis|CamBA]] [http://sourceforge.net/projects/camba]
* Fiasco/FIAT [http://www.stat.cmu.edu/~fiasco]
* [[FreeSurfer]] [http://surfer.nmr.mgh.harvard.edu]
* [[mrVista]][http://white.stanford.edu/newlm/index.php/Software]
* [[FMRIB Software Library|FSL]] [http://www.fmrib.ox.ac.uk/fsl]
* [[Statistical parametric mapping|SPM]] [http://www.fil.ion.ucl.ac.uk/spm]
* [http://www.imagilys.com/autospm.html AutoSPM: Automated SPM for Surgical Planning]
* [http://www.bioimagesuite.org BioImage Suite]
* [http://www.nordicimaginglab.com/ nordicICE]

==See also==
* [[Brain Mapping]]
* [[Brain function]]
* [[Event related fMRI]]
* [[Spinal fMRI]]
* [[Signal enhancement by extravascular water protons | SEEP fMRI]]
* [[EEG-fMRI]]
* [[Real-time fMRI]]
* [[Functional neuroimaging]]
* [[The fMRI Data Centre]]
* [[Linear transform model]]

==References==
<references/>

===Textbooks===
Scott A. Huettel, Allen W. Song, Gregory McCarthy, ''Functional Magnetic Resonance Imaging'', Sinauer Associates, 2004, ISBN 0-87893-288-7

Richard B. Buxton, ''An Introduction to Functional Magnetic Resonance Imaging: Principles and Techniques'', Cambridge Univ Press, 2002, ISBN 0-52158-113-3

===Journal articles===
{{cite journal
| author=Weiller C ''et al''
| title=Clinical potential of brain mapping using MRI
| journal=Journal of Magnetic Resonance Imaging
| year=2006
| volume=23
| issue=6
| pages= 840–850}}

{{cite journal
| author=Lin, Lyons, and Berkowitz
| title=Somatotopic Identification of Language-SMA in Language Processing via fMRI
| journal=Journal of Scientific and Practical Computing
| year=2007
| volume=1
| issue=2
| pages= 3–8}}
[http://www.spclab.com/publisher/journals/Vol1No2/L1.pdf]

== External links ==
* [http://www.biophysics.mcw.edu Department of Biophysics] at [[Medical College of Wisconsin]]
* [[Laboratory of Neuro Imaging]] at [[UCLA]]
* [[Athinoula A. Martinos Center for Biomedical Imaging]] [http://www.nmr.mgh.harvard.edu/martinos] at [[Massachusetts General Hospital]], which develops and supports [[FreeSurfer]]
* [http://radiologyinfo.org/en/info.cfm?pg=fmribrain RadiologyInfo]- The radiology information resource for patients: Functional Magnetic Resonance Imaging of the Brain
* [http://www.fmridc.org The fMRI Data Center (fMRIDC)] at [[Dartmouth College]]
* [http://www.fil.ion.ucl.ac.uk The Functional Imaging Laboratory] at [[University College London]]
* [http://www.fmrib.ox.ac.uk The Centre for Functional Magnetic Resonance Imaging of the Brain] at [[Oxford University]]
* [http://www.magres.nottingham.ac.uk/projects/ Sir Peter Mansfield Magnetic Resonance Centre,] University of Nottingham
* [http://www-bmu.psychiatry.cam.ac.uk The Brain Mapping Unit (BMU)], [[University of Cambridge]]
* [http://www.fmri.org/fmri.htm About fMRI] from [http://www.fmri.org/ Functional MRI Research Center], [[Columbia University]]
* [http://www.fmrib.ox.ac.uk/fmri_intro/ Introduction to FMRI] from the [http://www.fmrib.ox.ac.uk/ Oxford Centre for Functional Magnetic Resonance Imaging of the Brain], [[Oxford University]]
* [http://sccn.ucsd.edu/fmrlab/index.html FMRLAB] Toolbox for fMRI data analysis
* [http://www.brainmapping.org BrainMapping.ORG project] Community web site for information Brain Mapping and methods
* [https://www.ynic.york.ac.uk York Neuroimaging Center] at [[University of York]]
* [http://fmri.pl fMRI.pl Functional Imaging Lab] at [[Warsaw University of Technology]]
* [http://www.neuroimago.usp.br Functional Neuroimaging Lab] at [[University of Sao Paulo - Ribeirao Preto - Brazil]]
* [http://www.mri-tutorial.com/tutorial_fmri.html A list of the best introductions to fMRI on the web]
* [http://www.fmrimethods.org/ fMRI Methods Wiki] - with advice on how to report on fMRI studies
* [http://www.scholarpedia.org/article/Functional_magnetic_resonance_imaging fMRI entry at Scholarpedia]

==Notes==
{{reflist}}

[[Category:Magnetic resonance imaging]]
[[Category:Medical tests]]
[[Category:Neuroimaging]]
[[Category:Cognitive science]]

[[de:Funktionelle Magnetresonanztomographie]]
[[el:Λειτουργική Απεικόνιση Μαγνητικού Συντονισμού]]
[[fr:Imagerie par résonance magnétique fonctionnelle]]
[[is:Starfræn segulómmyndun]]
[[it:Risonanza magnetica funzionale]]
[[hu:Funkcionális mágneses rezonancia-vizsgálat]]
[[nl:Functionele MRI]]
[[ja:FMRI]]
[[no:Funksjonell Magnetresonanstomografi]]
[[pl:Funkcjonalny magnetyczny rezonans jądrowy]]
[[pt:Ressonância magnética]]
[[zh:功能性磁共振成像]]

Talk:Functional magnetic resonance imaging

2008-05-28T00:38:40Z

PhineasG: /* Is fMRI worthwhile */

{{WikiProjectBanners
|1={{WPMED|class=B|importance=mid}}
|2={{WikiProject Neuroscience|class=B|importance=high}}
}}

== History ==
I just like to comment on the fact that the history bit on fMRI is a bit misleading here. While Ogawa found the BOLD effect in 1990 by
effectively manipulating the oxygen saturation of the blood either directly or by insulin injections, he merely suggested that this
technique could complement PET functional imaging in some way. Of course everyone "knew" this was a possible route to fMRI, Ogawa's group
was held back by the fact that they believed the effect could only be observed at high fields > 4T, and their 4T human magnet did not
come online till years later. The first fMRI study ever was done by John Belliveau at MGH and published in Science 1991, although it
used a paramagnetic contrast agent rather than the BOLD effect. The first BOLD studies came out in 1992, one by Ogawa (PNAS),
one by Ken Kwong (PNAS) (there is a wikipedia entry for him already), and one by Peter Bandettini (MRM). —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/71.126.226.41|71.126.226.41]] ([[User talk:71.126.226.41|talk]]) 05:18, 10 May 2008 (UTC) 

== boustrophedonic? ==

Can someone check the meaning of this word? Is this actually used in the fMRI literature? Even if it is, it should be spelled out.

* Replace! I concur. Definitely not used in MRI literature. —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/129.132.154.237|129.132.154.237]] ([[User talk:129.132.154.237|talk]]) 14:05, 16 January 2008 (UTC) 

* I don't think it is used. I vote to replace this word.

Boustrophedon literally means "as an ox plows" and refers to the direction of scanning. If the scan is left to right on the first line, then right to left on the second line, etc on alternating lines, then it is boustrophedonic. If the scan is always left to right (like the raster of a TV screen) with silent retrace, then it is not boustrophedonic. [[User:Greensburger|Greensburger]] 14:44, 4 February 2007 (UTC)

I've never heard the word used in reference to MRI (okay, I've never heard the word used at all). I vote for its replacement. Better than that, why not remove the whole paragraph? Maybe we need a separate page describing EPI, which would go into k-space details. There is nothing about fMRI that inherently requires an alternating trajectory, and it seems odd to mention it without first explaining k-space. Reading the section again, the whole section doesn't make much sense. I'm not a functional person, but I guess the section should say something like B0 correction->motion correction->spatial/temporal filtering->correlation to stimuli. Any comments? [[User:Arthurtech|Arthurtech]] 18:35, 13 May 2007 (UTC)

A quick search of the journal 'Magnetic Resonance in Medicine' showed no hits for boustrophedon. It doesn't belong here. [[User:Arthurtech|Arthurtech]] 20:37, 15 May 2007 (UTC)

:Removed. [[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 00:33, 28 May 2008 (UTC)

== Who wrote this page? ==
Who wrote this page? -Anon

:Lots of people, it's a community effort as are all wikipedia pages. Go to the bottom of the article page and you will see a link called "page history", click on it and you will see a list of edits to the page along with who made those edits. [[User:Theresa knott|theresa knott]] 20:52, 4 May 2004 (UTC)

== Subtitle of the brain movie is suspicious ==

Can anyone check that? It should be an MRI video, rather than an fMRI video, even though fMRI information could be superimposed on those frames to get better resolution, which has always been done.

:I can't speak authoritatively for all cases, but typically fMRI data is of significantly lower spatial resolution than structural scans. Superimposing functionals is usually done for other purposes than to get better structure, e.g. to allow analysis across temporal/stimulus axes. --[[User:Improv|Improv]] 18:31, 9 Mar 2005 (UTC)

::Isn't the purpose of superimposing functionals over structurals to see where in the brain the activation is? I guess it's the structural image that must be stretched to match the reference image. --[[User:Almostc|AlmostC]] 18:11, 1 June 2006 (UTC)

==Is fMRI worthwhile==

This is an important section and should be included, people need to be made aware of the fundamental arguments which underlie functional imaging. (and no, those references weren't mine).

* I agree; it is important to mention the criticisms against fMRI raised by other scientists, and even if the section needs some work it shouldn't be deleted. [[User:Gccwang|Gccwang]] 04:02, 1 January 2006 (UTC)

::There are clearly debates over the proper design, analysis, and interpretation of fMRI studies. However, I don't believe there is any serious doubt in the neuroscientific community that the technique itself is tremendously useful. As is stated in the current version of this section, fMRI is only as useful as the experiment designed around it, as with any other technique. Thus I've changed the title of this section to better reflect the general (scientific) consensus. [[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 00:38, 28 May 2008 (UTC)

== What are "hemodynamic signals"? ==

It would be nice to have a potted description of the "hemodynamic signals" that appear in the first paragraph.

Sadly, the entry elsewhere on "hemodynamics" isn't much help, which may explain why it isn't linked from here http://en.wikipedia.org/wiki/Hemodynamics.

Michael Kenward

=="CBF"==

Near the end of the third paragraph, what is "CBF"? Is it "cerebral blood flow"?

Lance ==)------------

Yes.

==New research==
Recently, a [http://www.sciencenews.org/articles/20051217/fob5.asp report] was published in the Proceedings of the National Academy of Sciences documenting a "brain-training" session with both healthy and chronic-pain volunteers who studied their own brain activity while being "instructed" in useful ways to minimize pain perception and were able to significantly reduce pain after a mere 39 minutes of practice in the machine. This was contrasted with control and comparison groups who either were not in the machine, were given others' brain data, were instructed in various [[biofeedback]] techniques or were given data about a different section of the brain than that thought to control pain perception. Those who were being presented with data from their own ''rostral anterior singulate cortex'' in real-time during their training session reported reductions in experienced pain of more than half, while the other groups did not.

To me, this seems worthy of inclusion in the fMRI article, perhaps alongside a section about possible future uses, or at least noteworthy current experiments.

Also, is this phrase in need of a change or addendum? "To this date, fMRI has neither proven therapeutic value nor known damage to the human body."

[[User:67.171.194.78|67.171.194.78]] 04:53, 25 December 2005 (UTC)

*Let's wait for it to settle down as being an established scientific fact. This is too new to be considered reliable, and there hasn't been time for followup studies and criticisms to be published yet. If in 6 months it's considered well-founded, then it may be worthwhile to include. --[[User:Improv|Improv]] 05:02, 25 December 2005 (UTC)

**Perhaps just a category for current research? It seems some examples should be presented, even if they're general. [[User:67.171.194.78|67.171.194.78]] 05:10, 25 December 2005 (UTC)
***There's always a lot of research being done on this. If we dip our toe into those waters, we'll be kept impossibly busy covering facts that are distant from being accepted science. --[[User:Improv|Improv]] 06:11, 25 December 2005 (UTC)
:::*I agree with [[User:Improv|Improv]] here: there's just too much fMRI research going on for a "current projects" section. [[User:Semiconscious|Semiconscious]] 06:16, 25 December 2005 (UTC)

*The author ([[Christopher deCharms]]) actually started a company (omneuron.com) to implement this neurofeedback technique, which to me is promising. A similar work is by Rainer Goebel (inventor of BrainVoyager), where ping-pong balls in a game are controlled by such biofeedbacks read from fMRI of visual cortex. In my view, these works represent a growing branch and are worth included into the current research section. By all means, if such serious work is "distant from accepted science" (User:Improv), the "fMRI lie detector" is at a much longer distance from any serious science, and shall be deleted.--[[User:Schlieren|Schlieren]] 04:05, 11 July 2006 (UTC)

==Article removed from [[Wikipedia:Good articles]]==

This article was formerly listed as a [[Wikipedia:Good article|good article]], but was removed from the listing because the article fails to [[WP:CITE|cite]] and [[WP:RS|references]]. --''[[User: Allen3|Allen3]]'' [[User talk:Allen3|talk]] 11:52, 16 January 2006 (UTC)

==Comparisons to PET==

Could a comparison to PET (in terms of resolution, cost, safety, usage, etc.) be included somewhere on the page? I'm no expert on either, but it seems like this would be a natural thing to include given that both tecnologies try to measure CBF. [[User:128.42.167.200|128.42.167.200]] 20:33, 11 April 2006 (UTC)
:Good idea. MEG and EEG would be other good comparison targets. There's a figure in circulation (most textbooks) comparing spatial and temporal resolution of functional imaging techniques. I'll try to find/post it without treading on copyrights. --[[User:Joshnpowell|Josh Powell]] 00:04, 9 July 2006 (UTC)

== Pharmacological challenge functional MRI ==

I don't see any entries for p/ph-MRI. Am I looking in the wrong place, or has nobody written an article yet? [[User:Jddriessen|Jddriessen]] 14:30, 14 April 2007 (UTC)

== Event-related fMRI ==

I'm new to Wikipedia and just created my first article, [[efMRI]]. In retrospect it should be part of this article. How do I do that?

[[User:Abe (or Abraham)|Abe (or Abraham)]] 03:08, 12 September 2007 (UTC)

== Merging ==
* These articles should really be merged under the heading '''BOLD fMRI''' which is both more accurate and comprehensive. Other existing and emerging MRI techniques are also referred to as "functional MRI" but with respect to gastric function, muscular function or even brain function revealed by mechanisms other than the BOLD effect e.g. ''arterial spin labeling'' (ASL).

* Regarding merging with [[Real-time fMRI]]: I think ''Real-time fMRI'' should be its own article. It is sufficiently large. [[User:Fnielsen|fnielsen]] 15:21, 16 November 2007 (UTC)

* Real-time fMRI is only one paragraph, excluding reference. It should be merged into the main article. [[Blood-oxygen-level_dependent|BOLD]] should also be merged in. If they grow within the article, then perhaps they can be summarized within the article and described in detail in their own articles. -[[User:Kslays|kslays]] 19:50, 3 December 2007 (UTC)

* Regarding merging with [[Real-time fMRI]]: I think ''Real-time fMRI'' should be its own article. It is a distinct area of the field, and significant advances are underway

*Merged the one paragraph from BOLD into this article and redirected the BOLD article to here. I removed the merge suggestion tags [[User:Kpmiyapuram|Kpmiyapuram]] ([[User talk:Kpmiyapuram|talk]]) 16:57, 2 April 2008 (UTC)

== Newsweek article on fMRI mind reading ==

Check [http://www.newsweek.com/id/91688 this] out. I am very skeptical, but it's in the press, so people will look at the wiki article for further info. [[User:L'omo del batocio|L'omo del batocio]] ([[User talk:L'omo del batocio|talk]]) 11:07, 10 February 2008 (UTC). The PloS ONE article is available [http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0001394 here]. [[User:L'omo del batocio|L'omo del batocio]] ([[User talk:L'omo del batocio|talk]]) 11:50, 10 February 2008 (UTC)

== 2 citations ==

Only 2 references?
--[[User:1000Faces|1000Faces]] ([[User talk:1000Faces|talk]]) 02:48, 28 February 2008 (UTC)

== Beyond Blobology ==

Perhaps it should be mentioned that there is some kind of critizism about "Blobology" and the scarce interpretation of the pictures generated (as far as I understand it), see for instance:
http://www-bmu.psychiatry.cam.ac.uk/sitewide/publications/presentations/bullmore04mul.pdf - this Term slowly dissipates into German for instance, as "Blobologie" [[User:Plehn|Plehn]] ([[User talk:Plehn|talk]]) 09:54, 9 April 2008 (UTC)

Talk:Functional magnetic resonance imaging

2008-05-28T00:33:42Z

PhineasG: /* boustrophedonic? */

{{WikiProjectBanners
|1={{WPMED|class=B|importance=mid}}
|2={{WikiProject Neuroscience|class=B|importance=high}}
}}

== History ==
I just like to comment on the fact that the history bit on fMRI is a bit misleading here. While Ogawa found the BOLD effect in 1990 by
effectively manipulating the oxygen saturation of the blood either directly or by insulin injections, he merely suggested that this
technique could complement PET functional imaging in some way. Of course everyone "knew" this was a possible route to fMRI, Ogawa's group
was held back by the fact that they believed the effect could only be observed at high fields > 4T, and their 4T human magnet did not
come online till years later. The first fMRI study ever was done by John Belliveau at MGH and published in Science 1991, although it
used a paramagnetic contrast agent rather than the BOLD effect. The first BOLD studies came out in 1992, one by Ogawa (PNAS),
one by Ken Kwong (PNAS) (there is a wikipedia entry for him already), and one by Peter Bandettini (MRM). —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/71.126.226.41|71.126.226.41]] ([[User talk:71.126.226.41|talk]]) 05:18, 10 May 2008 (UTC) 

== boustrophedonic? ==

Can someone check the meaning of this word? Is this actually used in the fMRI literature? Even if it is, it should be spelled out.

* Replace! I concur. Definitely not used in MRI literature. —Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/129.132.154.237|129.132.154.237]] ([[User talk:129.132.154.237|talk]]) 14:05, 16 January 2008 (UTC) 

* I don't think it is used. I vote to replace this word.

Boustrophedon literally means "as an ox plows" and refers to the direction of scanning. If the scan is left to right on the first line, then right to left on the second line, etc on alternating lines, then it is boustrophedonic. If the scan is always left to right (like the raster of a TV screen) with silent retrace, then it is not boustrophedonic. [[User:Greensburger|Greensburger]] 14:44, 4 February 2007 (UTC)

I've never heard the word used in reference to MRI (okay, I've never heard the word used at all). I vote for its replacement. Better than that, why not remove the whole paragraph? Maybe we need a separate page describing EPI, which would go into k-space details. There is nothing about fMRI that inherently requires an alternating trajectory, and it seems odd to mention it without first explaining k-space. Reading the section again, the whole section doesn't make much sense. I'm not a functional person, but I guess the section should say something like B0 correction->motion correction->spatial/temporal filtering->correlation to stimuli. Any comments? [[User:Arthurtech|Arthurtech]] 18:35, 13 May 2007 (UTC)

A quick search of the journal 'Magnetic Resonance in Medicine' showed no hits for boustrophedon. It doesn't belong here. [[User:Arthurtech|Arthurtech]] 20:37, 15 May 2007 (UTC)

:Removed. [[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 00:33, 28 May 2008 (UTC)

== Who wrote this page? ==
Who wrote this page? -Anon

:Lots of people, it's a community effort as are all wikipedia pages. Go to the bottom of the article page and you will see a link called "page history", click on it and you will see a list of edits to the page along with who made those edits. [[User:Theresa knott|theresa knott]] 20:52, 4 May 2004 (UTC)

== Subtitle of the brain movie is suspicious ==

Can anyone check that? It should be an MRI video, rather than an fMRI video, even though fMRI information could be superimposed on those frames to get better resolution, which has always been done.

:I can't speak authoritatively for all cases, but typically fMRI data is of significantly lower spatial resolution than structural scans. Superimposing functionals is usually done for other purposes than to get better structure, e.g. to allow analysis across temporal/stimulus axes. --[[User:Improv|Improv]] 18:31, 9 Mar 2005 (UTC)

::Isn't the purpose of superimposing functionals over structurals to see where in the brain the activation is? I guess it's the structural image that must be stretched to match the reference image. --[[User:Almostc|AlmostC]] 18:11, 1 June 2006 (UTC)

==Is fMRI worthwhile==

This is an important section and should be included, people need to be made aware of the fundamental arguments which underlie functional imaging. (and no, those references weren't mine).

* I agree; it is important to mention the criticisms against fMRI raised by other scientists, and even if the section needs some work it shouldn't be deleted. [[User:Gccwang|Gccwang]] 04:02, 1 January 2006 (UTC)

== What are "hemodynamic signals"? ==

It would be nice to have a potted description of the "hemodynamic signals" that appear in the first paragraph.

Sadly, the entry elsewhere on "hemodynamics" isn't much help, which may explain why it isn't linked from here http://en.wikipedia.org/wiki/Hemodynamics.

Michael Kenward

=="CBF"==

Near the end of the third paragraph, what is "CBF"? Is it "cerebral blood flow"?

Lance ==)------------

Yes.

==New research==
Recently, a [http://www.sciencenews.org/articles/20051217/fob5.asp report] was published in the Proceedings of the National Academy of Sciences documenting a "brain-training" session with both healthy and chronic-pain volunteers who studied their own brain activity while being "instructed" in useful ways to minimize pain perception and were able to significantly reduce pain after a mere 39 minutes of practice in the machine. This was contrasted with control and comparison groups who either were not in the machine, were given others' brain data, were instructed in various [[biofeedback]] techniques or were given data about a different section of the brain than that thought to control pain perception. Those who were being presented with data from their own ''rostral anterior singulate cortex'' in real-time during their training session reported reductions in experienced pain of more than half, while the other groups did not.

To me, this seems worthy of inclusion in the fMRI article, perhaps alongside a section about possible future uses, or at least noteworthy current experiments.

Also, is this phrase in need of a change or addendum? "To this date, fMRI has neither proven therapeutic value nor known damage to the human body."

[[User:67.171.194.78|67.171.194.78]] 04:53, 25 December 2005 (UTC)

*Let's wait for it to settle down as being an established scientific fact. This is too new to be considered reliable, and there hasn't been time for followup studies and criticisms to be published yet. If in 6 months it's considered well-founded, then it may be worthwhile to include. --[[User:Improv|Improv]] 05:02, 25 December 2005 (UTC)

**Perhaps just a category for current research? It seems some examples should be presented, even if they're general. [[User:67.171.194.78|67.171.194.78]] 05:10, 25 December 2005 (UTC)
***There's always a lot of research being done on this. If we dip our toe into those waters, we'll be kept impossibly busy covering facts that are distant from being accepted science. --[[User:Improv|Improv]] 06:11, 25 December 2005 (UTC)
:::*I agree with [[User:Improv|Improv]] here: there's just too much fMRI research going on for a "current projects" section. [[User:Semiconscious|Semiconscious]] 06:16, 25 December 2005 (UTC)

*The author ([[Christopher deCharms]]) actually started a company (omneuron.com) to implement this neurofeedback technique, which to me is promising. A similar work is by Rainer Goebel (inventor of BrainVoyager), where ping-pong balls in a game are controlled by such biofeedbacks read from fMRI of visual cortex. In my view, these works represent a growing branch and are worth included into the current research section. By all means, if such serious work is "distant from accepted science" (User:Improv), the "fMRI lie detector" is at a much longer distance from any serious science, and shall be deleted.--[[User:Schlieren|Schlieren]] 04:05, 11 July 2006 (UTC)

==Article removed from [[Wikipedia:Good articles]]==

This article was formerly listed as a [[Wikipedia:Good article|good article]], but was removed from the listing because the article fails to [[WP:CITE|cite]] and [[WP:RS|references]]. --''[[User: Allen3|Allen3]]'' [[User talk:Allen3|talk]] 11:52, 16 January 2006 (UTC)

==Comparisons to PET==

Could a comparison to PET (in terms of resolution, cost, safety, usage, etc.) be included somewhere on the page? I'm no expert on either, but it seems like this would be a natural thing to include given that both tecnologies try to measure CBF. [[User:128.42.167.200|128.42.167.200]] 20:33, 11 April 2006 (UTC)
:Good idea. MEG and EEG would be other good comparison targets. There's a figure in circulation (most textbooks) comparing spatial and temporal resolution of functional imaging techniques. I'll try to find/post it without treading on copyrights. --[[User:Joshnpowell|Josh Powell]] 00:04, 9 July 2006 (UTC)

== Pharmacological challenge functional MRI ==

I don't see any entries for p/ph-MRI. Am I looking in the wrong place, or has nobody written an article yet? [[User:Jddriessen|Jddriessen]] 14:30, 14 April 2007 (UTC)

== Event-related fMRI ==

I'm new to Wikipedia and just created my first article, [[efMRI]]. In retrospect it should be part of this article. How do I do that?

[[User:Abe (or Abraham)|Abe (or Abraham)]] 03:08, 12 September 2007 (UTC)

== Merging ==
* These articles should really be merged under the heading '''BOLD fMRI''' which is both more accurate and comprehensive. Other existing and emerging MRI techniques are also referred to as "functional MRI" but with respect to gastric function, muscular function or even brain function revealed by mechanisms other than the BOLD effect e.g. ''arterial spin labeling'' (ASL).

* Regarding merging with [[Real-time fMRI]]: I think ''Real-time fMRI'' should be its own article. It is sufficiently large. [[User:Fnielsen|fnielsen]] 15:21, 16 November 2007 (UTC)

* Real-time fMRI is only one paragraph, excluding reference. It should be merged into the main article. [[Blood-oxygen-level_dependent|BOLD]] should also be merged in. If they grow within the article, then perhaps they can be summarized within the article and described in detail in their own articles. -[[User:Kslays|kslays]] 19:50, 3 December 2007 (UTC)

* Regarding merging with [[Real-time fMRI]]: I think ''Real-time fMRI'' should be its own article. It is a distinct area of the field, and significant advances are underway

*Merged the one paragraph from BOLD into this article and redirected the BOLD article to here. I removed the merge suggestion tags [[User:Kpmiyapuram|Kpmiyapuram]] ([[User talk:Kpmiyapuram|talk]]) 16:57, 2 April 2008 (UTC)

== Newsweek article on fMRI mind reading ==

Check [http://www.newsweek.com/id/91688 this] out. I am very skeptical, but it's in the press, so people will look at the wiki article for further info. [[User:L'omo del batocio|L'omo del batocio]] ([[User talk:L'omo del batocio|talk]]) 11:07, 10 February 2008 (UTC). The PloS ONE article is available [http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0001394 here]. [[User:L'omo del batocio|L'omo del batocio]] ([[User talk:L'omo del batocio|talk]]) 11:50, 10 February 2008 (UTC)

== 2 citations ==

Only 2 references?
--[[User:1000Faces|1000Faces]] ([[User talk:1000Faces|talk]]) 02:48, 28 February 2008 (UTC)

== Beyond Blobology ==

Perhaps it should be mentioned that there is some kind of critizism about "Blobology" and the scarce interpretation of the pictures generated (as far as I understand it), see for instance:
http://www-bmu.psychiatry.cam.ac.uk/sitewide/publications/presentations/bullmore04mul.pdf - this Term slowly dissipates into German for instance, as "Blobologie" [[User:Plehn|Plehn]] ([[User talk:Plehn|talk]]) 09:54, 9 April 2008 (UTC)

Functional magnetic resonance imaging

2008-05-28T00:33:11Z

PhineasG: /* Approaches to fMRI data analysis */

'''Functional [[magnetic resonance imaging]] (fMRI)''' measures the [[haemodynamic response]] related to [[neuron|neural]] activity in the [[brain]] or [[spinal cord]] of [[human]]s or other animals. It is one of the most recently developed forms of [[neuroimaging]].

[[Image:FMRI.jpg|thumb|250px|right|fMRI data (yellow) overlaid on an average of the brain anatomies of several humans (gray)]]

== Background ==

Since the 1890s (Roy and [[Charles Scott Sherrington|Sherrington]], 1890) it has been known that changes in [[blood flow]] and blood oxygenation in the [[brain]] (collectively known as [[hemodynamics]]) are closely linked to neural activity. When nerve cells are active they consume [[oxygen]] carried by [[hemoglobin]] in [[red blood cells]] from local [[capillary|capillaries]]. The local response to this oxygen utilization is an increase in blood flow to regions of increased neural activity, occurring after a delay of approximately 1-5 seconds. This hemodynamic response rises to a peak over 4-5 seconds, before falling back to baseline (and typically undershooting slightly). This leads to local changes in the relative concentration of oxyhemoglobin and deoxyhemoglobin and changes in local cerebral [[blood volume]] in addition to this change in local [[cerebral blood flow]].

'''Blood-oxygen-level dependent''' or BOLD fMRI is a method of observing which areas of the [[brain]] are active at any given time. It was found by Dr. [[Seiji Ogawa]]<ref>Ogawa, S., Lee, T.M., Nayak, A.S., and Glynn, P. (1990). Oxygenation-sensitive contrast in magnetic resonance image of rodent brain at high magnetic fields. Magn Reson Med 14, 68-78 </ref> and Dr. [[Robert Turner (Scientist)|Robert Turner]], working independently, in 1990. [[Neurons]] do not have internal reserves of energy in the form of [[sugar]] and [[oxygen]], so their firing causes a need for more energy to be brought in quickly. Through a process called the [[hemodynamic response]], blood releases oxygen to them at a greater rate than to inactive neurons, and the difference in [[magnetic susceptibility]] between oxyhemoglobin and [[Hemoglobin|deoxyhemoglobin]], and thus oxygenated or deoxygenated [[blood]], leads to magnetic signal variation which can be detected using an MRI scanner. Given many repetitions of a thought, action or experience, statistical methods can be used to determine the areas of the brain which reliably have more of this difference as a result, and therefore which areas of the brain are active during that thought, action or experience.

Almost all fMRI research uses BOLD as the method for determining where activity occurs in the brain as the result of various experiences, but because the signals are relative, and not individually quantitative, some question its rigor. Other methods which propose to measure neural activity directly have been attempted (for example, measurement of the Oxygen Extraction Fraction, or OEF, in regions of the brain, which measures how much of the oxyhemoglobin in the blood has been converted to deoxyhemoglobin<ref>[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&list_uids=7869897&dopt=Citation Theory of NMR signal behavior in magnetically inho...[Magn Reson Med. 1994] - PubMed Result]</ref>), but because the electromagnetic fields created by an active or firing neuron are so weak, the [[signal-to-noise ratio]] is extremely low and [[Statistics|statistical]] methods used to extract quantitative data have been largely unsuccessful as of yet.

[[Hemoglobin]] is [[diamagnetic]] when oxygenated but [[paramagnetic]] when deoxygenated. The [[magnetic resonance]] (MR) signal of blood is therefore slightly different depending on the level of oxygenation. These differential signals can be detected using an appropriate MR pulse sequence as [[blood-oxygen-level dependent]] (BOLD) contrast. Higher BOLD signal intensities arise from increases in the concentration of oxygenated [[hemoglobin]] since the blood [[magnetic susceptibility]] now more closely matches the tissue magnetic susceptibility. By collecting data in an [[MRI]] scanner with parameters sensitive to changes in magnetic susceptibility one can assess changes in BOLD contrast. These changes can be either positive or negative depending upon the relative changes in both cerebral blood flow (CBF) and oxygen consumption. Increases in CBF that outstrip changes in oxygen consumption will lead to increased BOLD signal, conversely decreases in CBF that outstrip changes in oxygen consumption will cause decreased BOLD signal intensity.

==Neural correlates of BOLD==
The precise relationship between neural signals and BOLD is under active research. In general, changes in BOLD signal are well correlated with changes in blood flow. Numerous studies during the past several decades have identified a coupling between blood flow and [[Metabolism|metabolic rate]]; that is, the blood supply is tightly regulated in space and time to provide the nutrients for brain metabolism. However, [[neuroscience|neuroscientists]] have been seeking a more direct relationship between the blood supply and the neural inputs/outputs that can be related to observable electrical activity and circuit models of brain function.

While current data indicate that [[local field potential]]s, an index of integrated electrical activity, form a marginally better correlation with blood flow than the spiking [[action potential]]s that are most directly associated with neural communication, no simple measure of electrical activity to date has provided an adequate correlation with metabolism and the blood supply across a wide dynamic range. Presumably, this reflects the complex nature of metabolic processes, which form a superset with regards to electrical activity. Some recent results have suggested that the increase in cerebral blood flow (CBF) following neural activity is not causally related to the metabolic demands of the brain region, but rather is driven by the presence of [[neurotransmitter]]s, especially [[Glutamic acid|glutamate]].

Some other recent results suggest that an initial small, negative dip before the main positive BOLD signal is more highly localized and also correlates with measured local decreases in tissue oxygen concentration (perhaps reflecting increased local [[metabolism]] during neuron activation). Use of this more localized negative BOLD signal has enabled imaging of human [[ocular dominance columns]] in [[Visual cortex|primary visual cortex]], with resolution of about 0.5 mm. One problem with this technique is that the early negative BOLD signal is small and can only be seen using larger scanners with magnetic fields of at least 3 [[Tesla (unit)|Tesla]]. Further, the signal is much smaller than the normal BOLD signal, making extraction of the signal from noise that much more difficult. Also, this initial dip occurs within 1-2 seconds of stimulus initiation, which may not be captured when signals are recorded at long repetition (TR). If the TR is sufficiently low, increased speed of the cerebral blood flow response due to consumption of vasoactive drugs (such as caffeine<ref>{{cite journal
| author=Behzadi, Y. ''et al''
| title=Caffeine reduces the initial dip in the visual bold response at 3 t.
| journal=Neuroimage
| year=2006
| volume=32
| pages=9-15
| doi=10.1016/j.neuroimage.2006.03.005
}}
</ref>) or natural differences in vascular responsivnesses may further obscure observation of the initial dip.

The BOLD signal is composed of CBF contributions from larger arteries and veins, smaller arterioles and venules, and capillaries. Experimental results indicate that the BOLD signal can be weighted to the smaller vessels, and hence closer to the active neurons, by using larger magnetic fields. For example, whereas about 70% of the BOLD signal arises from larger vessels in a 1.5 tesla scanner, about 70% arises from smaller vessels in a 4 tesla scanner. Furthermore, the size of the BOLD signal increases roughly as the square of the magnetic field strength. Hence there has been a push for larger field scanners to both improve localization and increase the signal. A few 7 tesla commercial scanners have become operational, and experimental 8 and 9 tesla scanners are under development.

[[Image:brain chrischan.jpg|thumb|250px|right|A sagittal slice of a Structural [[MRI]] scan of a human head. The nose is to the left.[[:Image:brain chrischan 300.gif|Click here]] to view an animated sequence of slices.]]

[[Image:User-FastFission-brain-frame44.png|thumb|250px|right|A slice of an [[MRI]] scan of the brain. The forehead is at the top and the back of the head is at the bottom. [[:Image:User-FastFission-brain.gif|Click here]] to view an animation of the scan from top to bottom.]]

== Technique ==

BOLD effects are measured using rapid volumetric acquisition of images with contrast weighed by T2 or T2* (see [[MRI]]). Such images can be acquired with moderately good spatial and temporal resolution; images are usually taken every 1–4 seconds, and the [[voxel]]s in the resulting image typically represent cubes of tissue about 2–4 millimeters on each side in humans. Recent technical advancements, such as the use of high magnetic fields and advanced "multichannel" RF reception, have advanced spatial resolution to the millimeter scale. Although responses to stimuli presented as close together as one or two seconds can be distinguished from one another, using a method known as event-related fMRI, the full time course of a BOLD response to a briefly presented stimulus lasts about 15 seconds for the robust positive response.

== fMRI studies draw from many disciplines ==

To use fMRI effectively, an investigator must have a firm grasp of the relevant principles from all of these fields:

* [[Physics]]: Researchers should have a reasonable understanding of the physical principles underlying fMRI.
* [[Psychology]]: Almost all fMRI studies are essentially [[cognitive psychology|cognitive psychological]], [[physiological psychology|cognitive psychophysiological]], and/or [[psychophysics|psychophysical]] experiments in which the MRI scanner is used to obtain an extra set of measurements in addition to behavioral and [[electroencephalographic]] measurements. This allows for more detailed theory testing and inference on perceptual and cognitive processes, and allows to relate these to specific brain structures.
* [[Neuroanatomy]]: The fMRI signals can be put into the context of previous knowledge only with an understanding of the neuroanatomy. Ultimately, the goal of all functional imaging experiments is to explain [[human cognition]] and behavior in terms of physical (anatomical) mechanisms.
* [[Statistics]]: Correct application of statistics is essential to "tease out" observations and avoid [[Type I and type II errors|false-positive]] results.
* [[Electrophysiology]]: Familiarity with neuronal behavior at the electrophysiological level can help investigators design a useful fMRI study.

[[Seiji Ogawa]] and [[Kenneth Kwong]] are generally credited as the discoverers of the BOLD effect that underlies conventional fMRI.

==Is fMRI worthwhile?==
Since its inception, fMRI has been strongly criticised, both as a research technique and in the way its results have been interpreted.

===Criticisms leveled at fMRI===

* The BOLD signal is only an indirect measure of neural activity, and is therefore susceptible to influence by non-neural changes in the body.

* BOLD signals are most strongly associated with the input to a given area than with the output. It is therefore possible (although unlikely) that a BOLD signal could be present in a given area even if there is no single unit activity.<ref>{{cite journal
| author=Logothetis, N.K.
| year=2001
| title=Neurophysiological investigation of the basis of the fMRI signal.
| journal=Nature
| volume=412
| url=http://www.ssc.uwo.ca/psychology/culhamlab/fmri/pdfs/Logothetis.pdf

| pages=150

| doi=10.1038/35084005
}}</ref>

* Different brain areas may have different hemodynamic responses, which would not be accurately reflected by the [[general linear model]] often used to filter fMRI time signals.

* fMRI has often been used to ask "where" activations take place in the brain. This has led to the charge that it is simply a modern-day [[phrenology]]. Most scientists prefer models which explain "how" psychological mechanisms function. The counter-argument to this criticism is that knowing "where" a cognitive function is located is vitally important. Neuropsychology, invasive manipulation of brain function and functional imaging each give us different windows of understanding into what each brain region does. The analogy to phrenology is somewhat misleading: [[Phrenology]] has little or no basis in science, but fMRI permits strong inferences to be made and tested within the [[scientific method]].

* fMRI has often been used to show activation localized to specific regions, and do not reflect the distributed nature of processing in [[Biological neural network|neural networks]]. Several recent [[multivariate]] statistical techniques work around this issue by characterizing interactions between "active" regions found via traditional [[univariate]] techniques. Such techniques might prove useful in the future.

* For a non-invasive scan, fMRI has moderately good spatial resolution. However, the temporal response of the blood supply, which is the basis of fMRI, is poor relative to the electrical signals that define neuronal communication. Therefore, some research groups are working around this issue by combining fMRI with data collection techniques such as [[electroencephalography]] (EEG) or [[magnetoencephalography]] (MEG). EEG has much higher temporal resolution but rather poor spatial resolution, whereas MEG has much higher temporal resolution and similar spatial resolution. This has led some to suggest MEG is a more valuable tool than fMRI.

* Many theoretical models used to explain fMRI signals are so poorly specified that they are not [[Falsifiability|falsifiable]] (a central tenet from the [[scientific method]]). Hence, some argue, fMRI is not really a "science". The counter-argument is that an fMRI study can provide evidence to falsify a prior theory if it is well-designed. Also, well-specified mathematical and computational models of the neural processes underlying fMRI can make theories more concrete, allowing them to make predictions that can be verified or falsified by fMRI.

===General counterargument===

Like any other technique, fMRI is as worthwhile as the design of the experiment using it. Many investigators have used fMRI ineffectively because they were not familiar with all aspects of the technique, or because they received their academic training in disciplines characterized by less rigor than some other branches of psychology and neuroscience. Ineffective use of the technique is a problem for the field, but it is not a consequence of the technique itself.

While the mechanistic information provided by fMRI is limited relative to classical techniques of electrophysiology and molecular biology, this is a general criticism of systems-level biology based upon changes in metabolism, blood supply, or ensemble indices of electrical activity. Most researchers believe that both "bottom-up" and "top-down" measurements are needed to inform our understanding of the complex mechanisms that transpose neural activity into behavior.

===Advantages of fMRI===

* It can noninvasively record brain signals (of humans and other animals) without risks of radiation inherent in other scanning methods, such as [[Computed tomography|CT]] scans.
* It can record on a spatial resolution in the region of 3-6 millimeters, but with relatively poor temporal resolution (in the order of seconds) compared with techniques such as EEG. However, this is mainly because of the phenomena being measured, not because of the technique. EEG measures electrical/neural activity while fMRI measures blood activity, which has a longer response. The MRI equipment used for fMRI can be used for high temporal resolution, if one measures different phenomena.

=== Commercial use ===
''Omneuron'' [http://www.omneuron.com/] is a US-based company founded by [[Christopher deCharms]] that is researching potential practical and clinical applications of real time fMRI.

''Applied fMRI Institute'' [http://www.appliedfmri.org] is a [[San Diego, CA]] based company offering commercial use of their [[Siemens]] 3T TIM Trio.

''Neurognostics'' [http://www.neurognostics.com/] is a US-based company that offers a standardized fMRI system

''Imagilys'' [http://www.imagilys.com/] is a European company specialized in clinical and research fMRI.

At least two companies have been set up to use fMRI in [[lie detection]]. They are ''No Lie MRI, Inc'' [http://www.noliemri.com/] and ''Cephos Corporation'' [http://www.cephoscorp.com/]. In episode 109 of the popular science show [[Mythbusters]], the three members of the build team attempted to fool an FMRI test. Although two of them were unsuccessful, the third was able to successfully fool the machine.

The signals are extrapolated from the fMRI machine onto a screen, displaying the active regions of the brain. Depending on what regions are the most active, the technician can determine whether a subject is telling the truth or not. This technology is in its early stages of development, and many of its proponents hope to replace older lie detection techniques.

== Scanning in practice ==

[[Image:Varian4T.jpg|thumb|250px|right|[[University of California, Berkeley|Berkeley's]] 4T fMRI scanner.]]
Subjects participating in a fMRI experiment are asked to lie still and are usually restrained with soft pads to prevent small motions from disturbing measurements. Some labs also employ bite bars to reduce motion, although these are unpopular as they can cause some discomfort to subjects. It is possible to correct for some amount of head movement with post-processing of the data, but large transient motion can render these attempts futile. Generally motion in excess of 3 millimeters will result in unusable data. The issue of motion is present for all populations, but most notably within populations that are not physically or emotionally equipped for even short MRI sessions (e.g., those with [[Alzheimer's Disease]] or [[schizophrenia]], or young children). In these populations, various and negative [[reinforcement]] strategies can be employed in an attempt to attenuate motion artifacts, but in general the solution lies in designing a compatible paradigm with these populations.

An fMRI experiment usually lasts between 15 minutes and 2 hours. Depending on the purpose of study, subjects may view movies, hear sounds, smell odors, perform cognitive tasks such as memorization or imagination, press a few buttons, or perform other tasks. Researchers are required to give detailed instructions and descriptions of the experiment plan to each subject, who must sign a consent form before the experiment.

Safety is a very important issue in all experiments involving MRI. Potential subjects must ensure that they are able to enter the MRI environment. Due to the nature of the MRI scanner, there is an extremely strong magnetic field surrounding the MRI scanner (at least 1.5 [[tesla (unit)|teslas]], possibly stronger). Potential subjects must be thoroughly examined for any ferromagnetic objects (e.g. watches, glasses, hair pins, pacemakers, bone plates and screws, etc.) before entering the scanning environment.

== Related techniques ==

Aside from fMRI, there are other related ways to probe brain activity using magnetic resonance properties:

===Contrast MR===
An injected [[Radiocontrast|contrast agent]] such as an [[iron oxide]] that has been coated by a [[sugar]] or [[starch]] (to hide from the body's defense system), causes a local disturbance in the [[magnetic field]] that is measurable by the MRI scanner. The signals associated with these kinds of contrast agents are proportional to the cerebral blood volume. While this semi-invasive method presents a considerable disadvantage in terms of studying brain function in normal subjects, it enables far greater detection sensitivity than BOLD signal, which may increase the viability of fMRI in clinical populations. Other methods of investigating blood volume that do not require an injection are a subject of current research, although no alternative technique in theory can match the high sensitivity provided by injection of contrast agent.

===Arterial spin labeling===
By magnetic labeling the proximal blood supply using "arterial spin labeling" ASL, the associated signal is proportional to the cerebral blood flow, or [[perfusion]]. This method provides more quantitative physiological information than BOLD signal, and has the same sensitivity for detecting task-induced changes in local brain function

===Magnetic resonance spectroscopic imaging===
Magnetic resonance spectroscopic imaging (MRS) is another, [[Nuclear magnetic resonance|NMR]]-based process for assessing function within the living brain. MRS takes advantage of the fact that [[proton]]s ([[hydrogen]] atoms) residing in differing chemical environments depending upon the molecule they inhabit (H2O vs. [[protein]], for example) possess slightly different resonant properties. For a given volume of brain (typically > 1 cubic cm), the distribution of these H resonances can be displayed as a [[spectroscopy|spectrum]].

The area under the peak for each resonance provides a quantitative measure of the relative abundance of that compound. The largest peak is composed of H2O. However, there are also discernible peaks for [[choline]], [[creatine]], [[N-Acetylaspartate|''N''-acetylaspartate]] (NAA) and [[lactic acid|lactate]]. Fortuitously, NAA is mostly inactive within the neuron, serving as a precursor to glutamate and as storage for acetyl groups (to be used in [[fatty acid]] synthesis) — but its relative levels are a reasonable approximation of neuronal integrity and functional status. Brain diseases ([[schizophrenia]], [[stroke]], certain [[tumor]]s, [[multiple sclerosis]]) can be characterized by the regional alteration in NAA levels when compared to healthy subjects. Creatine is used as a relative control value since its levels remain fairly constant, while choline and lactate levels have been used to evaluate [[brain tumor]]s.

===Diffusion tensor imaging===
[[Diffusion tensor imaging]] (DTI) is a related use of MR to measure anatomical connectivity between areas. Although it is not strictly a functional imaging technique because it does not measure dynamic changes in brain function, the measures of inter-area connectivity it provides are complementary to images of [[cerebral cortex|cortical]] function provided by BOLD fMRI. [[White matter]] bundles carry functional information between brain regions. The diffusion of water molecules is hindered across the axes of these bundles, such that measurements of water diffusion can reveal information about the location of large white matter pathways. Illnesses that disrupt the normal organization or integrity of cerebral white matter (such as multiple sclerosis) have a quantitative impact on DTI measures.

== Approaches to fMRI data analysis ==

The ultimate goal of fMRI data analysis is to detect correlations between brain activation and the task the subject performs during the scan. The BOLD signature of activation is relatively weak, however, so other sources of noise in the acquired data must be carefully controlled. This means that a series of processing steps must be performed on the acquired images before the actual statistical search for task-related activation can begin.

For a typical fMRI scan, the 3D volume of the subject's head is imaged every one or two seconds, producing a few hundred to a few thousand complete images per scanning session. The nature of MRI is such that these images are acquired in [[Fourier transform]] space, so they must be transformed back to image space to be useful. Because of practical limitations of the scanner the Fourier samples are not acquired on a grid, and scanner imperfections like thermal drift and spike noise introduce additional distortions. Small motions on the part of the subject and the subject's pulse and respiration will also affect the images.

The most common situation is that the researcher uses a [[mri#resonance and relaxation|pulse sequence]] supplied by the scanner vendor, such as an [[mri|imaging|echo-planar imaging (EPI)]] sequence that allows for relatively rapid acquisition of many images. Software in the scanner platform itself then performs the reconstruction of images from Fourier transform space. During this stage some information is lost (specifically the complex phase of the reconstructed signal). Some types of artifacts, for example spike noise, become more difficult to remove after reconstruction, but if the scanner is working well these artifacts are thought to be relatively unimportant. For pulse sequences not provided by the vendor, for example spiral EPI, reconstruction must be done by software running on a separate platform.

After reconstruction the output of the scanning session consists of a series of 3D images of the brain. The most common corrections performed on these images are motion correction and correction for physiological effects. Outlier correction and spatial and/or temporal filtering may also be performed. If the task performed by the subject is thought to produce bursts of activation which are short compared to the BOLD response time (on the order of 6 seconds), temporal filtering may be performed at this stage to attempt to [[deconvolution|deconvolve]] out the [[BOLD]] response and recover the temporal pattern of activation.

At this point the data provides a time series of samples for each voxel in the scanned volume. A variety of methods are used to correlate these voxel time series with the task in order to produce maps of task-dependent activation.

Some fMRI [[neuroimaging software]]:
* [[Analysis of Functional NeuroImages|AFNI]] [http://afni.nimh.nih.gov]
* [[BrainVoyager]] [http://www.brainvoyager.com]
* [[Cambridge Brain Analysis|CamBA]] [http://sourceforge.net/projects/camba]
* Fiasco/FIAT [http://www.stat.cmu.edu/~fiasco]
* [[FreeSurfer]] [http://surfer.nmr.mgh.harvard.edu]
* [[mrVista]][http://white.stanford.edu/newlm/index.php/Software]
* [[FMRIB Software Library|FSL]] [http://www.fmrib.ox.ac.uk/fsl]
* [[Statistical parametric mapping|SPM]] [http://www.fil.ion.ucl.ac.uk/spm]
* [http://www.imagilys.com/autospm.html AutoSPM: Automated SPM for Surgical Planning]
* [http://www.bioimagesuite.org BioImage Suite]
* [http://www.nordicimaginglab.com/ nordicICE]

==See also==
* [[Brain Mapping]]
* [[Brain function]]
* [[Event related fMRI]]
* [[Spinal fMRI]]
* [[Signal enhancement by extravascular water protons | SEEP fMRI]]
* [[EEG-fMRI]]
* [[Real-time fMRI]]
* [[Functional neuroimaging]]
* [[The fMRI Data Centre]]
* [[Linear transform model]]

==References==
<references/>

===Textbooks===
Scott A. Huettel, Allen W. Song, Gregory McCarthy, ''Functional Magnetic Resonance Imaging'', Sinauer Associates, 2004, ISBN 0-87893-288-7

Richard B. Buxton, ''An Introduction to Functional Magnetic Resonance Imaging: Principles and Techniques'', Cambridge Univ Press, 2002, ISBN 0-52158-113-3

===Journal articles===
{{cite journal
| author=Weiller C ''et al''
| title=Clinical potential of brain mapping using MRI
| journal=Journal of Magnetic Resonance Imaging
| year=2006
| volume=23
| issue=6
| pages= 840–850}}

{{cite journal
| author=Lin, Lyons, and Berkowitz
| title=Somatotopic Identification of Language-SMA in Language Processing via fMRI
| journal=Journal of Scientific and Practical Computing
| year=2007
| volume=1
| issue=2
| pages= 3–8}}
[http://www.spclab.com/publisher/journals/Vol1No2/L1.pdf]

== External links ==
* [http://www.biophysics.mcw.edu Department of Biophysics] at [[Medical College of Wisconsin]]
* [[Laboratory of Neuro Imaging]] at [[UCLA]]
* [[Athinoula A. Martinos Center for Biomedical Imaging]] [http://www.nmr.mgh.harvard.edu/martinos] at [[Massachusetts General Hospital]], which develops and supports [[FreeSurfer]]
* [http://radiologyinfo.org/en/info.cfm?pg=fmribrain RadiologyInfo]- The radiology information resource for patients: Functional Magnetic Resonance Imaging of the Brain
* [http://www.fmridc.org The fMRI Data Center (fMRIDC)] at [[Dartmouth College]]
* [http://www.fil.ion.ucl.ac.uk The Functional Imaging Laboratory] at [[University College London]]
* [http://www.fmrib.ox.ac.uk The Centre for Functional Magnetic Resonance Imaging of the Brain] at [[Oxford University]]
* [http://www.magres.nottingham.ac.uk/projects/ Sir Peter Mansfield Magnetic Resonance Centre,] University of Nottingham
* [http://www-bmu.psychiatry.cam.ac.uk The Brain Mapping Unit (BMU)], [[University of Cambridge]]
* [http://www.fmri.org/fmri.htm About fMRI] from [http://www.fmri.org/ Functional MRI Research Center], [[Columbia University]]
* [http://www.fmrib.ox.ac.uk/fmri_intro/ Introduction to FMRI] from the [http://www.fmrib.ox.ac.uk/ Oxford Centre for Functional Magnetic Resonance Imaging of the Brain], [[Oxford University]]
* [http://sccn.ucsd.edu/fmrlab/index.html FMRLAB] Toolbox for fMRI data analysis
* [http://www.brainmapping.org BrainMapping.ORG project] Community web site for information Brain Mapping and methods
* [https://www.ynic.york.ac.uk York Neuroimaging Center] at [[University of York]]
* [http://fmri.pl fMRI.pl Functional Imaging Lab] at [[Warsaw University of Technology]]
* [http://www.neuroimago.usp.br Functional Neuroimaging Lab] at [[University of Sao Paulo - Ribeirao Preto - Brazil]]
* [http://www.mri-tutorial.com/tutorial_fmri.html A list of the best introductions to fMRI on the web]
* [http://www.fmrimethods.org/ fMRI Methods Wiki] - with advice on how to report on fMRI studies
* [http://www.scholarpedia.org/article/Functional_magnetic_resonance_imaging fMRI entry at Scholarpedia]

==Notes==
{{reflist}}

[[Category:Magnetic resonance imaging]]
[[Category:Medical tests]]
[[Category:Neuroimaging]]
[[Category:Cognitive science]]

[[de:Funktionelle Magnetresonanztomographie]]
[[el:Λειτουργική Απεικόνιση Μαγνητικού Συντονισμού]]
[[fr:Imagerie par résonance magnétique fonctionnelle]]
[[is:Starfræn segulómmyndun]]
[[it:Risonanza magnetica funzionale]]
[[hu:Funkcionális mágneses rezonancia-vizsgálat]]
[[nl:Functionele MRI]]
[[ja:FMRI]]
[[no:Funksjonell Magnetresonanstomografi]]
[[pl:Funkcjonalny magnetyczny rezonans jądrowy]]
[[pt:Ressonância magnética]]
[[zh:功能性磁共振成像]]

Cortical area

2008-05-28T00:10:59Z

PhineasG:

A '''cortical area''' is a part of the [[cerebral cortex]].
===Functionally Defined===
Often, a cortical area is functionally defined, i.e. its neurons share certain distinguishing functional properties. For example, they are activated by the same category of [[stimulus (physiology)|stimuli]] or seem to be involved in similar [[cognition|cognitive]] tasks, that are different from the stimuli or tasks that activate neurons in the neighboring areas.

===Anatomically Defined===
Alternatively, cortical areas can be defined [[Histology|histo]]-[[anatomy|anatomically]], like the [[Brodmann area]]s. In some cases, both types of definition yield identical areas. An example is the [[primary visual cortex]], or V1, which is identical to Brodmann area 17.

===Connections between Areas===
Connections between cortical areas can be direct (cortico-cortical) or indirect (e.g. via the [[thalamus]] or [[basal ganglia]]).

{{neuroanatomy-stub}}
[[Category:Neuroanatomy]]

Talk:Brodmann area

2008-05-28T00:05:25Z

PhineasG:

{{WikiProject Neuroscience|class=Start|importance=High}}

== Infobox ==

Since this is not a brain region, but rather a method of classifying brain regions, the infobox really doesn't make sense. I'm replacing it with two images. -- '''[[User:Selket|Selket]]''' [[User_talk:Selket|Talk]] 07:07, 20 March 2007 (UTC)

:Does anyone known how to confirm that Brodmann's original drawings are in the public domain? (They must be, right?) And also know where to get good digital versions? It seems silly not to use his own drawings. [[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 00:05, 28 May 2008 (UTC)

Brodmann area

2008-05-28T00:02:32Z

PhineasG: expanded introductory/explanatory paragraph

Cytoarchitecture

2008-05-27T23:37:45Z

PhineasG:

'''Cytoarchitecture''' is the [[cell (biology)|cell]]ular composition of a bodily structure.

In [[biology]], it refers to the arrangement of cells in a [[Tissue (biology)|tissue]], and in [[neuroscience]] it refers specifically to the arrangement of [[neuron]]al [[soma]]s (cell bodies) in the [[brain]]. In [[neurobiology]], [[staining]] for grey matter in the brain would highlight its cytoarchitecture, since grey matter is in part defined by high concentrations of neuron cell bodies (as opposed to [[white matter]] which refers to areas with high concentrations of [[myelin]]ated [[axon|neuronal axons]]).

{{cell-biology-stub}}

[[no:Cytoarkitektur]]
[[Category:Histology]]

Laminar organization

2008-05-27T23:32:53Z

PhineasG:

{{dablink|This article is about organization of tissues in animal bodies. For another use of the term laminar, see [[laminar]].}}
'''Laminar organization''' describes the way certain [[biological tissue|tissues]], such as [[bone membrane]], [[skin]], or [[brain]] matter, are arranged in layers. The organization of the [[cerebral cortex]] can be described by its laminar organization, due to the arrangement of cortical [[neuron]]s into [[Cerebral cortex#Laminar pattern|six distinct layers]].
{{anatomy-stub}}

Talk:Jonathan Rothberg

2008-05-10T13:54:00Z

PhineasG:

{{WPBiography
|class=
|priority=
}}

This article seems to be mostly a copy-paste job from the Baylor website on Rothberg: http://www.bcm.edu/news/packages/rothberg-bio.cfm
[[User:PhineasG|PhineasG]] ([[User talk:PhineasG|talk]]) 13:54, 10 May 2008 (UTC)

African elephant

2008-05-08T14:56:00Z

PhineasG: /* Teeth */

{{Taxobox
| name = African elephants
| image = Elephant in Botswana.JPG
| image_width = 270px
| image_caption =
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| classis = [[Mammal]]ia
| ordo = [[Proboscidea]]
| familia = [[Elephantidae]]
| genus = '''''Loxodonta'''''
| genus_authority = Anonymous, 1827
| subdivision_ranks = [[Species]]
| subdivision =
''[[Loxodonta adaurora]]'' (extinct) 
''[[African Bush Elephant|Loxodonta africana]]'' 
''[[African Forest Elephant|Loxodonta cyclotis]]''
| range_map=African Elephant distribution map.svg
| range_map_caption=Distribution of ''Loxodonta africana'' (2007)
}}

'''African elephants''' are the two species of [[elephant]]s in the [[genus]] '''''Loxodonta''''', one of the two existing genera in [[Elephantidae]]. Although it is commonly believed that the genus was named by [[Georges Cuvier]] in 1825, Cuvier spelled it ''Loxodonte''. An anonymous author romanized the spelling to ''Loxodonta'' and the [[ICZN]] recognizes this as the proper authority.<ref name=MSW3>{{MSW3 Shoshani|pages=91}}</ref>

[[Fossil]] ''Loxodonta'' have only been found in [[Africa]], where they developed in the middle [[Pliocene]].

== Size ==
Males stand 3.64 meters (12 feet) tall at the shoulder and weigh 5455 kg (12,000 lbs), while females stand 3 meters (10 feet) and weigh 3636 kg to 4545 kg (8,000 to 11,000 lbs) <ref><http://www.pittsburghzoo.org/wildlife_lookUpAnimal_detail.asp?categoryname=&animal=15></ref>.

==Teeth==
Elephants have four molars; each weighs about 11 lbs and measures about 12 inches long. As the front pair wear down and drop out in pieces, the back pair shift forward and two new molars emerge in the back of the mouth. Elephants replace their teeth six times. At about 40 to 60 years of age the elephant no longer has teeth and will likely die of starvation, a common cause of death.

Their tusks are teeth; the second set of incisors become the tusks. They are used for digging for roots and stripping the bark off trees for food, for fighting each other during mating season, and for defending themselves against predators. The tusks weigh from 50-100 pounds and can be from 5 to 8 feet long. Both bulls and cows have tusks.
<ref><http://www.denverzoo.org/animals/asianElephant.asp></ref>.

== Species ==
*''Loxodonta adaurora'', [[extinct]], presumed antecedent of the modern African elephants.
*[[African Bush Elephant]] (''Loxodonta africana'').<ref name=MSW3/>
*[[African Forest Elephant]] (''Loxodonta cyclotis'').<ref name=MSW3/>

Bush and Forest Elephants were formerly considered [[subspecies]] of the same species ''Loxodonta africana''. However, they are nowadays generally considered to be two distinct species <ref name=MSW3/>. The African Forest Elephant has a longer and narrower mandible, rounder ears, a different number of toenails, straighter and downward tusks, and considerably smaller size. With regard to the number of toenails: the African Bush Elephant normally has 4 toenails on the front foot and 3 on the hind foot, the African Forest Elephant normally has 5 toenails on the front foot and 4 on the hind foot (like the Asian elephant), but hybrids between the two species commonly occur.

==Conservation==
[[Image:Ivory trade.jpg|thumb|upright|Men with African elephant tusks, [[Dar es Salaam]], c. 1900]]
Poaching significantly reduced the population of ''Loxodonta'' in certain regions during the 20th century. An example of this poaching pressure is in the eastern region of Chad—elephant herds there were substantial as recently as 1970, with an estimated population of 400,000; however, by 2006 the number had dwindled to about 10,000. The African elephant nominally has governmental protection, but [[poaching]] is still a serious issue.<ref>{{cite web | title = 100 Slaughtered Elephants Found in Africa | url = http://www.livescience.com/animalworld/060830_chad_elephants.html | author = Goudarzi, Sara | date = [[2006-08-30]] | accessdate = 2006-08-31 | work = [http://LiveScience.com LiveScience.com]}}</ref>

Human encroachment into or adjacent to natural areas where bush elephants occur has led to recent research into methods of safely driving groups of elephants away from humans, including the discovery that playback of the recorded sounds of angry [[Western honey bee|honey bees]] are remarkably effective at prompting elephants to flee an area.<ref>Lucy E. King, Iain Douglas-Hamilton, Fritz Vollrath (2007) African elephants run from the sound of disturbed bees. ''Current Biology'' 17: R832-R833</ref> Some elephant communities have grown so large, in Africa, that some communities have resorted to culling large amounts to help sustain the ecosystem.[http://news.bbc.co.uk/1/hi/world/africa/4392800.stm]

==Gallery==
<gallery>
Image:African_Elephant.jpg|A close-up from the Addo Elephant Park, South Africa.
Image:bull elephants small.jpg|Bull elephants mock fighting on the rim of Ngorongoro Crater, Tanzania.
Image:African elephant sabi.jpg|Bull elephant in the Sabi Sands of South Africa.
</gallery>
<gallery>
Image:Makuleke6.JPG|A breeding herd of elephants, entirely cows and young, in the [[Makuleke]] area of the Kruger Park, South Africa.
Image:Young bull elephant.jpg|A young bull elephant in a breeding herd displaying mock aggression.
</gallery>

==References==
{{reflist}}

==External links==
*[http://elephant.elehost.com/About_Elephants/about_elephants.htm Elephant Information Repository] - An in-depth resource on elephants
*[http://faculty.jsd.claremont.edu/dmcfarlane/MtElgon/index.htm "Elephant caves" of Mt Elgon National Park]
* [http://elephantvoices.org/ ElephantVoices] - Resource on elephant vocal communications
* [http://elephanttrust.org/ Amboseli Trust for Elephants] - Interactive web site

{{Proboscidea}}

[[Category:Elephants]]
[[Category:EDGE Species]]

[[ca:Elefant africà]]
[[da:Afrikansk savanneelefant]]
[[de:Afrikanischer Elefant]]
[[es:Elefante africano]]
[[fi:Afrikannorsut]]
[[he:פיל אפריקני]]
[[ja:アフリカゾウ属]]
[[li:Savanneolifant]]
[[nl:Afrikaanse olifanten]]
[[pl:Słoń afrykański]]
[[pt:Elefante africano]]
[[sl:Afriški slon]]
[[sv:Afrikansk elefant]]
[[tl:Elepante ng Aprika]]
[[ta:ஆப்பிரிக்க யானை]]
[[zh:非洲象]]
[[zh-yue:非洲象]]

Neocortex

2008-02-26T03:33:52Z

PhineasG: /* Evolution */

{{otheruses4|the region of the brain|the Crash Bandicoot villain|Doctor Neo Cortex}}
{{Infobox Brain|
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}}
The '''neocortex''' ([[Latin]] for "new [[bark]]" or "new [[rind]]") is a part of the [[brain]] of [[mammal]]s. It is the outer layer of the [[cerebral hemisphere]]s, and made up of six layers, labelled I to VI (with VI being the innermost and I being the outermost). The neocortex is part of the [[cerebral cortex]] (along with the [[archicortex]] and [[paleocortex]], which are cortical parts of the [[limbic system]]). It is involved in higher functions such as [[sense|sensory perception]], generation of [[motor cortex|motor commands]], spatial reasoning, [[consciousness|conscious thought]] and, in humans, [[language]]. Other names for the neocortex include '''neopallium''' ("new [[mantelpiece|mantle]]") and '''isocortex''' ("equal rind").

==Anatomy==
The neocortex consists of the [[grey matter]], or neuronal cell bodies and [[myelin|unmyelinated]] fibers, surrounding the deeper [[white matter]] ([[myelin|myelinated]] [[axons]]) in the [[cerebrum]]. Whereas the neocortex is smooth in [[rodents]] and other small mammals, it has deep grooves ([[sulcus (anatomy)|sulci]]) and wrinkles ([[gyrus|gyri]]) in [[primate]]s and other larger mammals. These folds increase the surface area of the neocortex considerably without taking up too much more volume. This has allowed primates and especially humans to evolve new functional areas of neocortex that are responsible for enhanced cognitive skills such as [[working memory]] and speech and language.

The neocortex contains two primary types of neurons, excitatory [[pyramidal neurons]] (~80% of neocortical neurons) and inhibitory [[interneurons]] (~20%). The structure of the neocortex is relatively uniform (hence the names "iso-" and "homotypic" cortex): it consists of six horizontal layers segregated principally by [[cell (biology)|cell]] type and [[neuron]]al connections. For example, pyramidal neurons in the upper layers II and III project their [[axons]] to other areas of neocortex, while those in the deeper layers V and VI project primarily out of the cortex, e.g. to the [[thalamus]], [[brainstem]], and [[spinal cord]]. Neurons in layer IV receive all of the [[synapse|synaptic connections]] from outside the cortex, and themselves make short-range, local connections to other cortical layers. Thus, layer IV receives all incoming sensory information and distributes it to the other layers for further processing.

The neurons of the neocortex are also arranged in vertical structures called [[cortical column|neocortical columns]]. These are patches of the neocortex with a diameter of about 0.5 mm (and a depth of 2 mm). Each column typically responds to a sensory stimulus representing a certain body part or region of [[sound]] or [[Visual perception|vision]]. These columns are similar, and can be thought of as the basic repeating functional units of the neocortex. In humans, the neocortex consists of about a half-million of these columns, each of which contains approximately 60,000 neurons.{{Fact|date=December 2007}}

The neocortex is divided into [[frontal lobe|frontal]], [[parietal lobe|parietal]], [[temporal lobe|temporal]], and [[occipital lobe|occipital]] lobes, which perform different functions. For example, the occipital lobe contains the [[primary visual cortex]], and the temporal lobe contains the [[primary auditory cortex]]. Further subdivisions or areas of neocortex are responsible for more specific cognitive processes. In humans, the [[frontal lobe]] contains areas devoted to abilities that are enhanced in or unique to our species, such as complex language processing localized to the ventrolateral prefrontal cortex ([[Broca's area]]) and social and emotional processing localized to the [[orbitofrontal cortex]]. (''See [[Cerebral cortex]] and [[Cerebrum]].'')

The female human neocortex contains approximately 19 billion [[neurons]] while the male human neocortex has 23 billion.<ref>{{cite journal | author=Pakkenberg B, Gundersen HJ | title=Neocortical neuron number in humans: effect of sex and age. | journal=J Comp Neurol | year=1997 Jul 28 | pages=312-20 | volume=384 | issue=2 | id=PMID 9215725}}</ref> Additionally, the female neocortex has more white matter, while the male neocortex contains more grey matter. The implications of such differences are not fully known.

==Evolution==
With respect to [[evolution]], the neocortex is the newest part of the [[cerebral cortex]] (hence the name "neo"); the other parts of the cerebral cortex are the [[paleocortex]] and [[archicortex]], collectively known as the [[allocortex]]. The cellular organization of the allocortex is different from the six-layer structure mentioned above. In humans, 90% of the cerebral cortex is neocortex.

The six-layer cortex appears to be a distinguishing feature of mammals; it has been found in the brains of all mammals, but not in any other animals. There is some debate,<ref>{{cite journal | author=Jarvis ED, Gunturkun O, Bruce L, Csillag A, Karten H, Kuenzel W, Medina L, Paxinos G, Perkel DJ, Shimizu T, Striedter G, Wild JM, Ball GF, Dugas-Ford J, Durand SE, Hough GE, Husband S, Kubikova L, Lee DW, Mello CV, Powers A, Siang C, Smulders TV, Wada K, White SA, Yamamoto K, Yu J, Reiner A, Butler AB | title=Avian brains and a new understanding of vertebrate brain evolution | journal=Nat Rev Neurosci | year=2005 | pages=151-9 | volume=6 | issue=2 | id=PMID 15685220}}</ref><ref>{{cite journal | author=Reiner A, Perkel DJ, Bruce LL, Butler AB, Csillag A, Kuenzel W, Medina L, Paxinos G, Shimizu T, Striedter G, Wild M, Ball GF, Durand S, Gunturkun O, Lee DW, Mello CV, Powers A, White SA, Hough G, Kubikova L, Smulders TV, Wada K, Dugas-Ford J, Husband S, Yamamoto K, Yu J, Siang C, Jarvis ED | title=Revised nomenclature for avian telencephalon and some related brainstem nuclei | journal=J Comp Neurol | year=2004 | pages=377-414 | volume=473 | issue=3 | id=PMID 15116397}}</ref> however, as to the cross-[[species]] nomenclature for ''neocortex''. In [[bird|avians]], for instance, there are clear examples of cognitive processes that are thought to be neocortical in nature, despite the lack of the distinctive six-layer neocortical structure. In a similar manner, [[reptile]]s, such as [[turtles]], have primary sensory cortices. A consistent, alternative name has yet to be agreed upon.

==See also==
* [[List of regions in the human brain]]
* [[Blue Brain]], a project to produce a computer simulation of a neocortical column and eventually a whole neocortex
* Software model of the neocortex by Jeff Hawkins (http://www.numenta.com/)
* Model of the neocortex by the Brain Engineering Laboratory at Dartmouth College (http://www.dartmouth.edu/~rhg/Research4Neo.html)
*[[Dr. Neo Cortex]], a fictional character of the [[Crash Bandicoot]] series, whose name is based on the neocortex.

==References==
<div class="references-small"><references /></div>

[[Category:Neuroanatomy]]
[[Category:Cerebrum]]

[[da:Neokortex]]
[[de:Neocortex]]
[[es:Neocórtex]]
[[nl:Neocortex]]
[[ja:大脳新皮質]]
[[pt:Neocórtex]]
[[ru:Новая кора]]
[[sv:Neocortex]]
[[zh:新皮质]]

Neocortex

2008-02-26T03:30:30Z

PhineasG: /* Anatomy */

{{otheruses4|the region of the brain|the Crash Bandicoot villain|Doctor Neo Cortex}}
{{Infobox Brain|
Name = {{PAGENAME}} |
Latin = |
GraySubject = |
GrayPage = |
Image = |
Caption = |
Image2 = |
Caption2 = |
IsPartOf = |
Components = |
Artery = |
Vein = |
BrainInfoType = ancil |
BrainInfoNumber = 754 |
MeshName = Neocortex |
MeshNumber = |
DorlandsPre = n_03 |
DorlandsSuf = 12561071 |
}}
The '''neocortex''' ([[Latin]] for "new [[bark]]" or "new [[rind]]") is a part of the [[brain]] of [[mammal]]s. It is the outer layer of the [[cerebral hemisphere]]s, and made up of six layers, labelled I to VI (with VI being the innermost and I being the outermost). The neocortex is part of the [[cerebral cortex]] (along with the [[archicortex]] and [[paleocortex]], which are cortical parts of the [[limbic system]]). It is involved in higher functions such as [[sense|sensory perception]], generation of [[motor cortex|motor commands]], spatial reasoning, [[consciousness|conscious thought]] and, in humans, [[language]]. Other names for the neocortex include '''neopallium''' ("new [[mantelpiece|mantle]]") and '''isocortex''' ("equal rind").

==Anatomy==
The neocortex consists of the [[grey matter]], or neuronal cell bodies and [[myelin|unmyelinated]] fibers, surrounding the deeper [[white matter]] ([[myelin|myelinated]] [[axons]]) in the [[cerebrum]]. Whereas the neocortex is smooth in [[rodents]] and other small mammals, it has deep grooves ([[sulcus (anatomy)|sulci]]) and wrinkles ([[gyrus|gyri]]) in [[primate]]s and other larger mammals. These folds increase the surface area of the neocortex considerably without taking up too much more volume. This has allowed primates and especially humans to evolve new functional areas of neocortex that are responsible for enhanced cognitive skills such as [[working memory]] and speech and language.

The neocortex contains two primary types of neurons, excitatory [[pyramidal neurons]] (~80% of neocortical neurons) and inhibitory [[interneurons]] (~20%). The structure of the neocortex is relatively uniform (hence the names "iso-" and "homotypic" cortex): it consists of six horizontal layers segregated principally by [[cell (biology)|cell]] type and [[neuron]]al connections. For example, pyramidal neurons in the upper layers II and III project their [[axons]] to other areas of neocortex, while those in the deeper layers V and VI project primarily out of the cortex, e.g. to the [[thalamus]], [[brainstem]], and [[spinal cord]]. Neurons in layer IV receive all of the [[synapse|synaptic connections]] from outside the cortex, and themselves make short-range, local connections to other cortical layers. Thus, layer IV receives all incoming sensory information and distributes it to the other layers for further processing.

The neurons of the neocortex are also arranged in vertical structures called [[cortical column|neocortical columns]]. These are patches of the neocortex with a diameter of about 0.5 mm (and a depth of 2 mm). Each column typically responds to a sensory stimulus representing a certain body part or region of [[sound]] or [[Visual perception|vision]]. These columns are similar, and can be thought of as the basic repeating functional units of the neocortex. In humans, the neocortex consists of about a half-million of these columns, each of which contains approximately 60,000 neurons.{{Fact|date=December 2007}}

The neocortex is divided into [[frontal lobe|frontal]], [[parietal lobe|parietal]], [[temporal lobe|temporal]], and [[occipital lobe|occipital]] lobes, which perform different functions. For example, the occipital lobe contains the [[primary visual cortex]], and the temporal lobe contains the [[primary auditory cortex]]. Further subdivisions or areas of neocortex are responsible for more specific cognitive processes. In humans, the [[frontal lobe]] contains areas devoted to abilities that are enhanced in or unique to our species, such as complex language processing localized to the ventrolateral prefrontal cortex ([[Broca's area]]) and social and emotional processing localized to the [[orbitofrontal cortex]]. (''See [[Cerebral cortex]] and [[Cerebrum]].'')

The female human neocortex contains approximately 19 billion [[neurons]] while the male human neocortex has 23 billion.<ref>{{cite journal | author=Pakkenberg B, Gundersen HJ | title=Neocortical neuron number in humans: effect of sex and age. | journal=J Comp Neurol | year=1997 Jul 28 | pages=312-20 | volume=384 | issue=2 | id=PMID 9215725}}</ref> Additionally, the female neocortex has more white matter, while the male neocortex contains more grey matter. The implications of such differences are not fully known.

==Evolution==
With respect to [[evolution]], the neocortex is the newest part of the [[cerebral cortex]] (hence the name "neo"); the other parts of the cerebral cortex are the [[paleocortex]] and [[archicortex]], collectively known as the [[allocortex]]. The cellular organization of the allocortex is different from the six-layer structure mentioned above. In humans, 90% of the cerebral cortex is neopallium.

The six-layer cortex appears to be a distinguishing feature of mammals; it has been found in the brains of all mammals, but not in any other animals. There is some debate,<ref>{{cite journal | author=Jarvis ED, Gunturkun O, Bruce L, Csillag A, Karten H, Kuenzel W, Medina L, Paxinos G, Perkel DJ, Shimizu T, Striedter G, Wild JM, Ball GF, Dugas-Ford J, Durand SE, Hough GE, Husband S, Kubikova L, Lee DW, Mello CV, Powers A, Siang C, Smulders TV, Wada K, White SA, Yamamoto K, Yu J, Reiner A, Butler AB | title=Avian brains and a new understanding of vertebrate brain evolution | journal=Nat Rev Neurosci | year=2005 | pages=151-9 | volume=6 | issue=2 | id=PMID 15685220}}</ref><ref>{{cite journal | author=Reiner A, Perkel DJ, Bruce LL, Butler AB, Csillag A, Kuenzel W, Medina L, Paxinos G, Shimizu T, Striedter G, Wild M, Ball GF, Durand S, Gunturkun O, Lee DW, Mello CV, Powers A, White SA, Hough G, Kubikova L, Smulders TV, Wada K, Dugas-Ford J, Husband S, Yamamoto K, Yu J, Siang C, Jarvis ED | title=Revised nomenclature for avian telencephalon and some related brainstem nuclei | journal=J Comp Neurol | year=2004 | pages=377-414 | volume=473 | issue=3 | id=PMID 15116397}}</ref> however, as to the cross-[[species]] nomenclature for ''neocortex''. In [[bird|avians]], for instance, there are clear examples of cognitive processes that are thought to be neocortical in nature, despite the lack of the distinctive six-layer neocortical structure. In a similar manner, [[reptile]]s, such as [[turtles]], have primary sensory cortices. A consistent, alternative name has yet to be agreed upon.

==See also==
* [[List of regions in the human brain]]
* [[Blue Brain]], a project to produce a computer simulation of a neocortical column and eventually a whole neocortex
* Software model of the neocortex by Jeff Hawkins (http://www.numenta.com/)
* Model of the neocortex by the Brain Engineering Laboratory at Dartmouth College (http://www.dartmouth.edu/~rhg/Research4Neo.html)
*[[Dr. Neo Cortex]], a fictional character of the [[Crash Bandicoot]] series, whose name is based on the neocortex.

==References==
<div class="references-small"><references /></div>

[[Category:Neuroanatomy]]
[[Category:Cerebrum]]

[[da:Neokortex]]
[[de:Neocortex]]
[[es:Neocórtex]]
[[nl:Neocortex]]
[[ja:大脳新皮質]]
[[pt:Neocórtex]]
[[ru:Новая кора]]
[[sv:Neocortex]]
[[zh:新皮质]]

Željko Ivanek

2008-02-26T03:07:37Z

PhineasG: /* Filmography */

{{Infobox actor
| name = Željko Ivanek
| image = replace this image.svg
| imagesize = 150px
| caption =
| birthname =
| birthdate = {{birth date and age|1957|8|15|mf=y}}
| birthplace = [[Ljubljana]], [[Slovenia]], [[Socialist Federal Republic of Yugoslavia|Yugoslavia]]
| deathdate =
| deathplace =
| spouse =
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'''Željko Ivanek''' (born [[August 15]], [[1957]]) is an American [[television]], [[film]], and [[theatre|stage]] [[actor]].

Ivanek was born in [[Ljubljana]], [[Slovenia]] (then a part of [[Yugoslavia]]) and emigrated with his parents to the United States in 1960.<ref>[http://www.filmreference.com/film/93/Zeljko-Ivanek.html Zeljko Ivanek Biography (1957-)]</ref> He graduated from [[Yale University]] in [[1978]] and afterward attended the [[London Academy of Music and Dramatic Art]].<ref>[http://movies.yahoo.com/movie/contributor/1800094065/bio Zeljko Ivanek Biography - Yahoo! Movies]</ref> Five years later, he originated the role of Hally in [[Athol Fugard]]'s play ''[[Master Harold...and the Boys]]''. He has also appeared in the U.S. premieres of such notable plays as [[Caryl Churchill]]'s ''[[Cloud Nine (play)|Cloud Nine]]'' and [[Martin McDonagh]]'s ''[[The Pillowman]]''.

He frequently appears on [[Broadway theatre|Broadway]] and has been nominated for three [[Tony Award]]s including one for his performance in the original production of ''[[Brighton Beach Memoirs]]'' , one as a featured actor in ''Two Shakespearean Actors'' and one for his lead performance as Queeg in a revival of ''[[The Caine Mutiny Court Martial]]'' alongside [[David Schwimmer]] and [[Tim Daly]].

He is perhaps best known for his supporting roles in the television series ''[[Homicide: Life on the Street]]'' (as prosecuting attorney Ed Danvers), ''[[Oz (TV series)|Oz]]'' ([[Governor James Devlin]]), and ''[[24 (TV series)|24]]'' ([[Andre Drazen]]). In [[2007]], he was cast as a regular in the [[Glenn Close]] [[FX (TV network)|FX]] series ''[[Damages (TV series)|Damages]]''. In his screen appearances he often plays professional men such as lawyers or government functionaries, sometimes of an evil nature.

==Filmography==
{| border="2" cellpadding="4" cellspacing="0" style="margin: 1em 1em 1em 0; background: #f9f9f9; border: 1px #aaa solid; border-collapse: collapse; font-size: 95%;"

! Year !! Film !! Role !! Other notes
|-
|rowspan="3"|1982 || ''[[The Soldier]]'' || Bombmaker ||
|-
|''[[Tex (film)|Tex]]'' || Hitchhiker ||
|-
|''[[The Sender]]'' || John Doe #83/The Sender ||
|-
|1984 ||''[[Mass Appeal]]''||Mark Dolson||
|-
|1987||''[[Rachel River]]''||Momo||
|-
|1990||''[[Artificial Paradise]]''||Willy||
|-
|1992||''[[School Ties]]''||Mr Cleary||
|-
|rowspan="4"|1996||''[[White Squall]]''||Coast Guard Captain Sanders||
|-
|''[[Courage Under Fire]]''||Ben Banacek||
|-
|''[[Infinity (film)|Infinity]]''||Bill Price||
|-
|''[[The Associate]]''||SEC Agent Thompkins||
|-
|rowspan="2"|1997||''[[Donnie Brasco]]''||Tim Curley||
|-
|''[[Julian Po]]''||Tom Potter||
|-
|rowspan="2"|1998||''[[Nowhere to Go]]''||Principal Jack Walker||
|-
|''[[A Civil Action]]''||Bill Crowley||
|-
|1999||''[[Snow Falling on Cedars]]''||Dr Whitman||
|-
|2000||''[[Dancer in the Dark]]''||District Attorney||
|-
|rowspan="2"|2001||''[[Hannibal (film)|Hannibal]]''||Dr Cordell Doemling||
|-
|''[[Black Hawk Down (film)|Black Hawk Down]]''||Harrell||
|-
|2002||''[[Unfaithful (film)|Unfaithful]]''||Detective Dean||
|-
|2003||''[[Dogville]]''||Ben||
|-
|2004||''[[The Manchurian Candidate]]''||Vaughn Utly||
|-
|2005||''[[Manderlay]]''||Dr Hector||
|-
|2006||''[[The Hoax]]''||Ralph Graves||
|-
|rowspan="2"|2007||''[[Ascension Day (film)|Ascension Day]]''||Master Travis||
|-
|''[[Live Free or Die Hard]]''||Molina||
|-
|2008||''[[In Bruges]]''||Canadian Guy||
|-
|}

==References==
{{reflist}}

==External links==
* {{imdb|0411964|name=Zeljko Ivanek}}
* {{ibdb|46288}}
*[http://www.americantheatrewing.org/seminars/detail/featured_performers_01_08 ''Working in the Theatre'': Featured Performers] video at [[American Theatre Wing|American Theatre Wing.org]], January 2008

{{DEFAULTSORT:Ivanek, Zeljko}}
[[Category:1957 births]]
[[Category:Alumni of LAMDA]]
[[Category:American film actors]]
[[Category:American stage actors]]
[[Category:American television actors]]
[[Category:Living people]]
[[Category:People from Ljubljana]]
[[Category:Slovenian actors]]
[[Category:Slovenian Americans]]
[[Category:Yale University alumni]]

[[nl:Željko Ivanek]]