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Encyclopedia > Corpus callosum
Brain: Corpus calosum
Corpus callosum from above. (Anterior portion is at the top of the image.)
Median sagittal section of brain (person faces to the left). Corpus callosum visible at center, in light gray.)
Gray's subject #189 828
NeuroNames hier-173
MeSH Corpus+Callosum

The corpus callosum is a structure of the mammalian brain in the longitudal fissure that connects the left and right cerebral hemispheres. It is the largest white matter structure in the brain, consisting of 200-250 million contralateral axonal projections. It is a wide, flat bundle of axons beneath the cortex. Much of the inter-hemispheric communication in the brain is conducted across the corpus callosum. Image File history File links Gray733. ... Image File history File links Gray720. ... It has been suggested that Human Anatomical Terms be merged into this article or section. ... NeuroNames is a system of nomenclature for the brain and related structures. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Subclasses Allotheria* Order Multituberculata (extinct) Order Volaticotheria (extinct) Order Palaeoryctoides (extinct) Order Triconodonta (extinct) Prototheria Order Monotremata Theria Infraclass Marsupialia Infraclass Eutheria The mammals are the class of vertebrate animals characterized by the production of milk in females for the nourishment of young, from mammary glands present on most species... In animals the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... The human brain as viewed from above, showing the cerebral hemispheres. ... White matter is one of the two main solid components of the central nervous system. ... It has been suggested that Human Anatomical Terms be merged into this article or section. ... An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... Location of the cerebral cortex Slice of the cerebral cortex, ca. ...


Monotremes and marsupials do not have a corpus callosum. Families †Kollikodontidae Ornithorhynchidae - Platypus Tachyglossidae - Echidnas †Steropodontidae Monotremes (monos, single + trema, hole; refers to the cloaca) are mammals that lay eggs instead of giving birth to live young like marsupials (Metatheria) and placental mammals (Eutheria). ... Orders Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Sparassodonta (extinct) Marsupials are mammals in which the female typically has a pouch (called the marsupium, from which the name Marsupial derives) in which it rears its young through early infancy. ...

Contents

Regions

The posterior portion of the corpus callosum is called the splenium; the anterior is called the genu (or "knee"); between the two is the body. It has been suggested that Human Anatomical Terms be merged into this article or section. ... The posterior end of the corpus callosum is the thickest part, and is termed the splenium. ... It has been suggested that Human Anatomical Terms be merged into this article or section. ... The anterior end of the corpus callosum is named the genu, and is bent downward and backward in front of the septum pellucidum; diminishing rapidly in thickness, it is prolonged backward under the name of the rostrum, which is connected below with the lamina terminalis. ...


The most anterior part is the rostrum. The anterior end of the corpus callosum is named the genu, and is bent downward and backward in front of the septum pellucidum; diminishing rapidly in thickness, it is prolonged backward under the name of the rostrum, which is connected below with the lamina terminalis. ...


In humans, disputed claims have been made about the importance for gender difference of a difference in size between the corpus callosum in males and females, and analogous racial claims. RB Bean, a Philadelphia anatomist, suggested in 1906 that the "exceptional size of the corpus callosum may mean exceptional intellectual activity" and claimed gender differences which were refuted by Franklin Mall, the director of his own laboratory.[1] 1906 (MCMVI) was a common year starting on Monday (see link for calendar). ...


Of much more substantial popular impact was a 1982 Science article claiming to be the first report of a reliable sex difference in human brain morphology and arguing for relevance to cognitive gender differences.[2] This paper appears to be the source of a large number of lay explanations of perceived male-female difference in behaviour: for example Newsweek stated in 1992 that the corpus callosum was "Often wider in the brains of women than in those of men, it may allow for greater cross talk between the hemispheres—possibly the basis for woman’s "intuition". It has also been used, for example, as the explanation of an increased single-task orientation of male, relative to female, learners; a smaller male corpus is said to make it harder for the left and right sides of the brain to work together and to explain a greater feminine ability to multitask. 1982 (MCMLXXXII) was a common year starting on Friday of the Gregorian calendar. ... Science, the journal of the American Association for the Advancement of Science (AAAS), is one of the worlds most prestigious scientific publications. ... The term morphology in biology refers to the outward appearance (shape, structure, colour, pattern) of an organism or taxon and its component parts. ... The Newsweek logo Newsweek is a weekly news magazine published in New York City and distributed throughout the United States and internationally. ... 1992 (MCMXCII) was a leap year starting on Wednesday. ... Intuition is an unconscious form of knowledge. ...


The relationship between known gender-specific biology (such as males having, in general, higher testosterone levels than females) and claims about behaviour (such as human males being more competitive) remains a highly contested one. Unusually, the scientific dispute in the case of the corpus callosum is not about the implications of biological difference, but whether such a difference actually exists. A substantial review paper performed a meta-analysis of 49 studies and found, contrary to de Lacoste-Utamsing and Holloway, that males have a larger corpus callosum, a relationship that is true whether or not account is taken of larger male brain size.[1] Bishop and Wahlstein found that "the widespread belief that women have a larger splenium than men and consequently think differently is untenable." However, more recent studies using new techniques revealed morphological sex differences in human corpus callosum.[3][4] Whether, and to what extent, these morphological differences are associated with behavioural and cognitive differences between males and females is unclear. Testosterone is a steroid hormone from the androgen group. ... Ralph Holloway (b. ...


Pathology

This article or section does not cite its references or sources. ... Agenesis of the Corpus Callosum (ACC) is a rare birth defect (congenital disorder) in which there is a complete or partial absence of the corpus callosum. ... Split-brain is the condition where the corpus callosum connecting the two halves of the brain is severed to some degree. ... Septo-optic dysplasia (SOD) is a congenital malformation syndrome manifested by hypoplasia (underdevelopment) of the optic nerve, hypopituitarism, and absence of the septum pellucidum (a midline part of the brain). ...

External links

BrainMaps is an NIH-funded interactive zoomable high-resolution digital brain atlas and virtual microscope that is based on more than 10 million megapixels (30 terabytes) of scanned images of serial sections of both primate and non-primate brains and that is integrated with a high-speed database for querying...

Additional images

References

  1. ^ a b Bishop, K.M. and D. Wahlsten. "Sex Differences in the Human Corpus Callosum: Myth or Reality?", Neuroscience and Biobehavioral Reviews, Vol. 21, No. 5, pp. 581–601, 1997.
  2. ^ de Lacoste-Utamsing, C., Holloway, R. L. "Sexual dimorphism in the human corpus callosum." Science, 216, 1431–1432, 1982.
  3. ^ Dubb A, Gur R, Avants B, Gee J. "Characterization of sexual dimorphism in the human corpus callosum." Neuroimage. 2003 Sep;20(1):512-9.
  4. ^ Shin YW, Kim DJ, Ha TH, Park HJ, Moon WJ, Chung EC, Lee JM, Kim IY, Kim SI, Kwon JS. "Sex differences in the human corpus callosum: diffusion tensor imaging study." Neuroreport. 2005 May 31;16(8):795-8.

  Results from FactBites:
 
TheFetus.net - Agenesis of the corpus callosum -Gianluigi Pilu, MD (2758 words)
Prenatal studies suggest that agenesis of the corpus callosum is found in 3% of all fetuses with ventriculomegaly[30] and in almost 10% of those with mild ventriculomegaly[31].
Isolated agenesis of the corpus callosum may be either a completely asymptomatic event or revealed during the course of a neurologic examination by subtle deficits, such as inability to match stimuli using both hands or to discriminate differences in temperature, shape, and weight in objects placed in both hands.
Frequency of agenesis of the corpus callosum in the developmentally disabled population as determined by computerized tomography.
corpus callosum - multiple sclerosis encyclopaedia (450 words)
The corpus callosum is an area of the brain that is fairly likely to be attacked in multiple sclerosis.
The corpus callosum is one of the two main connections between the two halves (hemispheres) of the brain (the other one is the anterior commissure).
The corpus callosum principally consists of about two hundred million white matter axons, some of which are normally myelinated (sheathed by an insulating substance called myelin) and some are not.
  More results at FactBites »

 
 

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