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Encyclopedia > Cerebral hemisphere
The human brain as viewed from above, showing the cerebral hemispheres. The anterior aspect (front) of the brain is to the right.

A cerebral hemisphere (hemispherium cerebrale) is defined as one of the two regions of the brain that are delineated by the body's median plane. The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres has an outer layer of grey matter called the cerebral cortex that is supported by an inner layer of white matter. The hemispheres are linked by the corpus callosum, a very large bundle of nerve fibers, and also by other smaller commissures, including the anterior commissure, posterior commissure, and hippocampal commissure. These commissures transfer information between the two hemispheres to coordinate localized functions. The architecture, types of cells, types of neurotransmitters and receptor subtypes are all distributed among the two hemispheres in a markedly asymmetric fashion. However, it must be noted that, while some of these hemispheric distribution differences are consistent across human beings, or even across some species, many observable distribution differences vary from individual to individual within a given species. Surface rendering of the human brain, viewed from above. ... Surface rendering of the human brain, viewed from above. ... The human brain controls the central nervous system (CNS), by way of the cranial nerves and spinal cord, the peripheral nervous system (PNS) and regulates virtually all human activity. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... In animals, the brain or encephalon (Greek for in the head), is the control center of the central nervous system, responsible for behaviour. ... The anatomical planes The anatomical position is a schematic convention for describing the relative morphology of the human body. ... Grey matter is a major component of the central nervous system, consisting of nerve cell bodies and short nerve cell extensions/processes (axons and dendrites). ... Location of the cerebral cortex Slice of the cerebral cortex, ca. ... White matter is one of the two main solid components of the central nervous system. ... The corpus callosum is a structure of the mammalian brain in the longitudal fissure that connects the left and right cerebral hemispheres. ... The Anterior Commissure (precommissure) is a bundle of white fibers, connecting the two cerebral hemispheres across the middle line, and placed in front of the columns of the fornix. ... The posterior commissure is a rounded band of white fibers crossing the middle line on the dorsal aspect of the upper end of the cerebral aqueduct. ... The lateral portions of the body of the fornix are joined by a thin triangular lamina, named the psalterium (lyra). ... Chemical structure of D-aspartic acid, a common amino acid neurotransmitter. ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ...

Contents

Embryological development

The cerebral hemispheres are derived from the telencephalon. They arise five weeks after conception as bilateral invaginations of the walls. The hemispheres grow round in a C-shape and then back again, pulling all structures internal to the hemispheres (such as the ventricles) with them. The interventricular foramen (sometimes called the interventricular foramena of munro) allows communication with the lateral ventricle. The choroid plexus is formed from ependymal cells and vascular mesenchyme. The telencephalon (te-len-seff-a-lon) is the technical name for a large region within the brain which is attributed many functions, which some groups would class as unique features which make humans stand out from other species. ... The term conception can refer to more than one meaning: Concept Fertilisation This is a disambiguation page — a navigational aid which lists pages that might otherwise share the same title. ... The ventricular system is a set of structures in the brain continuous with the central canal of the spinal cord. ... The choroid plexus is the area on the ventricles of the brain where cerebrospinal fluid (CSF) is produced by modified ependymal cells. ... Mesenchyme (also known as embryonic connective tissue) is the mass of tissue that develops mainly from the mesoderm (the middle layer of the trilaminar germ disc) of an embryo. ...


Bracken Corbin is fuckin hot


Hemisphere lateralization

Broad generalizations are often made in popular psychology about certain function (eg. logic, creativity) being lateralised, that is, located in the right or left side of the brain. These ideas need to be treated carefully because the popular lateralizations are often distributed across both sides.[1] However, there is some division of mental processing. Researchers have been investigating to what extent areas of the brain are specialized for certain functions. If a specific region of the brain is injured or destroyed, their functions can sometimes be recovered by neighboring brain regions - even opposite hemispheres. This depends more on the age and the damage occurred than anything else. The human brain is separated by a longitudinal fissure, separating the brain into two distinct cerebral hemispheres. ... This does not cite its references or sources. ...


The best evidence of lateralization for one specific ability is language. Both of the major areas involved in language skills, Broca's area and Wernicke's area, are in the left hemisphere. Perceptual information from the eyes, ears, and rest of the body is sent to the opposite hemisphere, and motor information sent out to the body also comes from the opposite hemisphere (see also primary sensory areas). Brocas area is the section of the human brain (in the opercular and triangular sections of the inferior frontal gyrus of the frontal lobe of the cortex) that is involved in language processing, speech production and comprehension. ... Wernickes area is a part of the human brain that forms part of the cortex, on the left posterior section of the superior temporal gyrus, encircling the auditory cortex, on the Sylvian fissure (part of the brain where the temporal lobe and parietal lobe meet). ... In psychology and the cognitive sciences, perception is the process of acquiring, interpreting, selecting, and organizing sensory information. ... The primary sensory areas are the main cerebral areas that receive sensory information from thalamic nerve projections. ...


Neuropsychologists (e.g. Roger Sperry, Michael Gazzaniga) have studied split-brain patients to better understand lateralization. Sperry pioneered the use of lateralized tachistoscopes to present visual information to one hemisphere or the other. Scientists have also studied people born without a corpus callosum to determine specialization of brain hemispheres. Drawing of the cells in the chicken cerebellum by S. Ramón y Cajal Neuroscience is a field that is devoted to the scientific study of the nervous system. ... ... Michael Gazzaniga is the David T. McLaughlin Distinguished University Professor at Dartmouth, where he is also Director of the Center for Cognitive Neuroscience. ... Split-brain is the condition where the corpus callosum connecting the two halves of the brain is severed to some degree. ... A tachistoscope is a device that displays (usually by projecting) an image for a specific amount of time. ... The corpus callosum is a structure of the mammalian brain in the longitudal fissure that connects the left and right cerebral hemispheres. ...


The magnocellular pathway of the visual system sends more information to the right hemisphere, while the parvocellular pathway sends more information to the left hemisphere. There are higher levels of the neurotransmitter norepinephrine on the right and higher levels of dopamine on the left. There is more white-matter (longer axons) on right and more grey-matter (cell bodies) on the left.[2] The visual system is the part of the nervous system which allows organisms to see. ... The parvocellular part of a nucleus in the brain (if the nucleus has a parvocellular part) is that part which contains small-bodied, punctate neuronal cells. ... Norepinephrine (INN)(abbr. ... Dopamine is a phenethylamine naturally produced by the human body. ...


Linear reasoning functions of language such as grammar and word production are often lateralized to the left hemisphere of the brain. In contrast, holistic reasoning functions of language such as intonation and emphasis are often lateralized to the right hemisphere of the brain. Other integrative functions such as intuitive or heuristic arithmetic, binaural sound localization, emotions, etc. seem to be more bilaterally controlled.[3] The word linear comes from the Latin word linearis, which means created by lines. ... For other uses, see Reason (disambiguation). ... Holism (from holon, a Greek word meaning entity) is the idea that the properties of a system cannot be determined or explained by the sum of its components alone. ... For other uses, see Reason (disambiguation). ... Look up Heuristic in Wiktionary, the free dictionary. ... For other uses, see Emotion (disambiguation). ...

Left brain functions Right brain functions
sequential simultaneous
analytical holistic
verbal imagistic
logical intuitive
linear algorithmic processing holistical algorithmic processing
mathematics: perception of counting/measurement mathematics: perception of shapes/motions[citation needed]
present and past present and future[citation needed]
language: grammar/words, pattern perception, literal language: intonation/emphasis, prosody, pragmatic, contextual

[4] The word linear comes from the Latin word linearis, which means created by lines. ... Holism (from holon, a Greek word meaning entity) is the idea that the properties of a system cannot be determined or explained by the sum of its components alone. ... Euclid, Greek mathematician, 3rd century BC, as imagined by by Raphael in this detail from The School of Athens. ... Euclid, Greek mathematician, 3rd century BC, as imagined by by Raphael in this detail from The School of Athens. ...


References

  1. ^ Western et al. 2006 "Psychology: Austraian and New Zealand edition" John Wiley p.107
  2. ^ R. Carter, Mapping the Mind, Phoenix, London, 2004, Originally Weidenfeld and Nicolson, 1998.
  3. ^ Dehaene S, Spelke E, Pinel P, Stanescu R, Tsivkin S. Sources of mathematical thinking: behavioral and brain-imaging evidence. Science. 1999 May 7;284(5416):970-4. PMID 10320379.
  4. ^ except the mathematics and time claims, which are both unreferenced, all from Taylor, Insep and Taylor, M. Martin (1990) "Psycholinguistics: Learning and using Language". page 367

Dr. Vilayanur Ramachandran on an episode of PBSs NOVA Television program. ... The Reith Lectures are a series of annual radio lectures given by leading figures of the day, and broadcast by the BBC. They were begun in 1948, in honour of the first Director-General of the BBC, John Reith. ...

See also

Image:Roger W Sperry. ... Michael Gazzaniga is the David T. McLaughlin Distinguished University Professor at Dartmouth, where he is also Director of the Center for Cognitive Neuroscience. ... Paul Pierre Broca (June 28, 1824 - July 9, 1880) was a French physician, anatomist and anthropologist. ... Manas Kumar Mandal is the Director of the Defence Institute of Psychological Research (DIPR), Delhi, India since January 5, 2004. ... Hemispherectomy is a medical procedure where one hemisphere (half) of the brain is removed. ...

External links


  Results from FactBites:
 
Cerebral hemisphere - Wikipedia, the free encyclopedia (922 words)
A cerebral hemisphere (hemispherium cerebrale) is defined as one of the two regions of the brain that are delineated by the body's median plane.
The frontal lobe is demarcated in red, the parietal lobe in orange, the occipital lobe in yellow, and the temporal lobe in green.
The hemispheres are linked by the corpus callosum, a very large bundle of nerve fibers, and also by other smaller commissures, including the anterior commissure, posterior commissure, and hippocampal commissure.
  More results at FactBites »

 
 

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