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Encyclopedia > Cerebral cortex
Location of the cerebral cortex
Location of the cerebral cortex
Slice of the cerebral cortex, ca. 10.5mm wide
Slice of the cerebral cortex, ca. 10.5mm wide
Golgi-stained neurons in the somatosensory cortex of the macaque monkey.

The cerebral cortex is a structure within the vertebrate brain with distinct structural and functional properties. In non-living, preserved brains, the outermost layers of the cerebrum has a grey color, hence the name "grey matter". Grey matter is formed by neurons and their unmyelinated fibers while the white matter below the grey matter of the cortex is formed predominantly by myelinated axons interconnecting different regions of the central nervous system. The human cerebral cortex is 2-4 mm (0.08-0.16 inches) thick and plays a central role in many complex brain functions including memory, attention, perceptual awareness, thought, language and consciousness. Look up cortex in Wiktionary, the free dictionary. ... Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ... Image File history File links Download high-resolution version (1400x1050, 2946 KB) Summary Golgi-stained neurons from somatosensory cortex in the macaque monkey. ... Image File history File links Download high-resolution version (1400x1050, 2946 KB) Summary Golgi-stained neurons from somatosensory cortex in the macaque monkey. ... This article does not cite any references or sources. ... The human brain In animals, the brain (enkephalos) (Greek for in the skull), is the control center of the central nervous system, responsible for behavior. ... 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. ... Achromatic redirects here. ... Neurons (also called nerve cells) are the primary cells of the nervous system. ... Myelin is an electrically insulating phospholipid layer that surrounds the axons of many neurons. ... 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. ... A diagram showing the CNS: 1. ... For other uses, see Memory (disambiguation). ... This article is about psychological concept of attention. ... In biological psychology, awareness describes a human or animals perception and cognitive reaction to a condition or event. ... Personification of thought (Greek Εννοια) in Celsus Library in Ephesos, Turkey Thought or thinking is a mental process which allows beings to model the world, and so to deal with it effectively according to their goals, plans, ends and desires. ... Consciousness is a quality of the mind generally regarded to comprise qualities such as subjectivity, self-awareness, sentience, sapience, and the ability to perceive the relationship between oneself and ones environment. ...


The surface of the cerebral cortex is folded in large mammals where more than two thirds of the cortical surface is buried in the grooves, called "sulci". The phylogenetically more ancient part of the cerebral cortex, the hippocampus, is differentiated in five layers of neurons, while the more recent neo-cortex is differentiated in six basic layers. Relative variations in thickness or cell type (among other parameters) allow us to distinguish between different neocortical architectonic fields. The geometry of these fields seems to be related to the anatomy of the cortical folds and, for example, layers in the upper part of the cortical grooves (called gyri) are more clearly differentiated than in its deeper parts (called sulcal "fundi"). Fold or folding may refer to: fold (geology) folding, in poker, is the act of withdrawing from a hand rather than meeting the bet folding ingredients together is a cooking technique protein folding origami, the art of paper folding pattern welding, the folding of metal This is a disambiguation page... Grays Fig. ... In biology, phylogenetics (Greek: phylon = tribe, race and genetikos = relative to birth, from genesis = birth) is the study of evolutionary relatedness among various groups of organisms (e. ... The hippocampus is structurally located inside the medial temporal lobe of the brain. ... The human brain In animals, the brain (enkephalos) (Greek for in the skull), is the control center of the central nervous system, responsible for behavior. ... Grays FIG. 726– Lateral surface of left cerebral hemisphere, viewed from the side. ...

Contents

Development

The cerebral cortex developed from the korta Mysan,a specialised part of the Mumintrollen ectoderm. The neural plate folds and closes to form the neural tube. From the cavity inside the neural tube develops the ventricular system, and, from the epithelial cells of its walls, the neurons and glial cells. The most-frontal part of the neural tube, the telencephalon, gives rise to the cerebral hemispheres and the neocortex. Organs derived from each germ layer. ... In the developing vertebrate nervous system, the neural tube is the precursor of the central nervous system, which comprises the brain and spinal cord. ... The ventricular system is a set of structures in the brain continuous with the central canal of the spinal cord. ... Neuroglia cells of the brain shown by Golgis method. ... 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 neocortex (Latin for new bark or new rind) is a part of the brain of mammals. ...


Most cortical neurons are generated within the ventricular zone close to the ventricles. Initially, progenitor cells in the ventricular zone divide symmetrically, producing two progenitor cells by mitotic cycle. Then, some progenitor cells begin to divide asymmetrically, producing one postmitotic cell that migrates radially and leaves the ventricular zone, and a daughter cell that continues to divide or that eventually dies. The migrating cells will become neurons.[1] Recent work has identified radial glial cells (also here) as one population of progenitor cells.[2] Mitosis divides genetic information during cell division. ... Radial glial cells are a pivotal cell type in the developing CNS involved in key developmental processes, ranging from patterning and neuronal migration to their newly described role as precursors during neurogenesis. ... Neuroglia cells of the brain shown by Golgis method. ...


During fetal and neonatal life, the immature cerebral cortex (the cortical plate) is sandwiched between two synaptic zones: the marginal zone above and an area just below the cortical plate, the subplate. The subplate is transient and disappears by approximately 2 months postnatal (Friauf, 1991).


Laminar pattern

The standard areas of cortex (isocortex) is characterized as having six distinct layers. From outside inward:

  1. Molecular layer
  2. External granular layer
  3. External pyramidal layer
  4. Internal granular layer
  5. Internal pyramidal layer
  6. Multiform layer.

After migration, neurons form efferents and receive afferent connections characteristic of their layer. It is interesting to note that during development, the inner layers are formed before the outer layers are. Efferent nerve fibers carry information away from the brain. ... In nervous systems, afferent signals or nerve fibers carry information toward the brain. ...

  1. The molecular layer I contains few scattered neurons and consists mainly of extensions of apical dendrites and horizontally oriented axons, and some Cajal-Retzius and spiny stellate neurons can be found.
  2. The external granular layer II contains small pyramidal neurons and numerous stellate neurons.
  3. The external pyramidal layer III contains predominantly small and medium sized pyramidal neurons, as well as non-pyramidal neurons with vertically-oriented intracortical axons. Layers I through III are the main target of interhemispheric corticocortical afferents, and layer III is the principal source of corticocortical efferents.
  4. The internal granular layer IV contains different types of stellate and pyramidal neurons, and is the main target of thalamocortical afferents as well as intra-hemispheric corticocortical afferents.
  5. The internal pyramidal layer V contains large pyramidal neurons (as the Betz cells in the primary motor cortex), as well as interneurons, and it is the principal source of efferent for all the motor-related subcortical structures.
  6. The multiform layer VI contains few large pyramidal neurons and many small spindle-like pyramidal and multiform neurons. The layer VI sends efferent fibers to the thalamus establishing a very precise reciprocal interconnection between the cortex and the thalamus (Creutzfeldt, 1995).

During early development, there is an additional layer of neurons present in the future white matter. these are called subplate neurons. They help organise neural connections in the developing brain and most disappear during postnatal development. Cajal-Retzius cells as drawn by Santiago Ramón y Cajal in 1891 The term Cajal–Retzius cell is applied to reelin-producing neurons of the human embryonic marginal zone which display, as a salient feature, radial ascending processes that contact the pial surface, and a horizontal axon plexus located... A pyramidal cell (or pyramidal neuron, or projection neuron) is a multipolar neuron located in the hippocampus and cerebral cortex. ... A pyramidal cell (or pyramidal neuron) is a multipolar neuron located in the hippocampus and cerebral cortex. ... In neuroscience, stellate cells are inhibitory interneurons found within the molecular layer of the cerebellum. ... A pyramidal cell (or pyramidal neuron) is a multipolar neuron located in the hippocampus and cerebral cortex. ... A pyramidal cell (or pyramidal neuron) is a multipolar neuron located in the hippocampus and cerebral cortex. ... This is about the polyhedron. ... Corticogenesis in a mouse brain. ...


The cortical layers are not simply stacked one over the other; they develop characteristic connections between different layers, which define the basic structure of the cortical columns in the mature cortex (Mountcastle, 1997). A cortical column is a group of neurons in the brain cortex which can be successively penetrated by a probe inserted perpendicularly to the cortical surface, and which have nearly identical receptive fields. ...


There are no actual borders between the layers, and neurons cross layer boundaries with their dendrites and axons trees all over. The pyramidal cells (the majority of the neurons) span at least three layers, and in many cases all the layers. Thus, it is not obvious that the layers have any functional significance. However, the flow of current in the cortical layers is consistent and shows inputs principally in layer IV, and the spread of activity, and thus the flow of information, roughly follows the models put forth by Martin, Whitteridge, and Somogyi in 1985. Neurons (also called nerve cells) are the primary cells of the nervous system. ... A pyramidal cell is a type of a neuron. ...


Connections of the cerebral cortex

The cerebral cortex is connected to various subcortical structures such as the thalamus and the basal ganglia sending information to them along efferent connections and receiving information from them via afferent connections. Most sensory information is routed to the cerebral cortex via the thalamus. Olfactory information, however, passes through the olfactory bulb to the olfactory (pyriform) cortex. The vast majority of connections are from one area of the cortex to another rather than to subcortical areas; Braitenberg and Schüz (1991) put the figure as high as 99%. The thalamus (from Greek θάλαμος = bedroom, chamber, IPA= /ˈθælÉ™mÉ™s/) is a pair and symmetric part of the brain. ... The basal ganglia (or basal nuclei) are a group of nuclei in the brain interconnected with the cerebral cortex, thalamus and brainstem. ... The olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors. ... Pears Pyriform comes from Pyri- meaning pear in latin and -form meaning shape in latin. ...


The cortex is commonly described as comprising three parts: sensory, motor and association areas.


Sensory areas

The sensory areas are the Areas that receive and process information from the senses. Parts of the cortex that receive sensory inputs from the thalamus are called primary sensory areas. The senses of vision, audition and touch are served by the primary visual cortex, primary auditory cortex and primary somatosensory cortex. In general, the two hemispheres receive the information from the opposite sides of the body. For example the right primary somatosensory cortex receives information from the left limbs and the right visual cortex receives information from the left visual field. The organisation of sensory maps in the cortex reflects that of the corresponding sensing organ, in which is known as a topographic map. Neighbouring points in the primary visual cortex, for example, correspond to neighbouring points in the retina. This topographic map is called a retinotopic map. In the same way, there exists a tonotopic map in the primary auditory cortex and a somatotopic map in the primary sensory cortex. This last topographic map of the body onto the Posterior Central Gyrus has been illustrated as deformed human representation, the somatosensory homunculus, where the size of different limbs reflects the importance of their innervation. A cortical area is a spatially confined unit of the cerebral cortex. ... Senses Senses are a UK based alternative rock band from Coventry. ... The thalamus (from Greek θάλαμος = bedroom, chamber, IPA= /ˈθæləməs/) is a pair and symmetric part of the brain. ... Brodmann area 17 (primary visual cortex) is shown in red in this image which also shows area 18 (orange) and 19 (yellow) The visual cortex refers to the primary visual cortex (also known as striate cortex or V1) and extrastriate visual cortical areas such as V2, V3, V4, and V5. ... The primary auditory cortex the region of the brain which is responsible for processing of auditory (sound) information. ... The lateral postcentral gyrus is a prominent structure in the parietal lobe of the human brain and an important landmark. ... For other uses, see Body (disambiguation). ... A topographic map is the ordered projection of one brain structure onto another, such as retinotopy, the ordered projection of the retina onto the lateral geniculated nucleus of the thalamus, and then onto the primary visual cortex, or somatotopy, the ordered projection of the body surface onto the primary sensory... Brodmann area 17 (primary visual cortex) is shown in red in this image which also shows area 18 (orange) and 19 (yellow) The visual cortex refers to the primary visual cortex (also known as striate cortex or V1) and extrastriate visual cortical areas such as V2, V3, V4, and V5. ... Human eye cross-sectional view. ... A topographic map is the ordered projection of one brain structure onto another, such as retinotopy, the ordered projection of the retina onto the lateral geniculated nucleus of the thalamus, and then onto the primary visual cortex, or somatotopy, the ordered projection of the body surface onto the primary sensory... Retinotopy is the concept that certain areas of the visual cortex are organized in a way that adjacent points in the visual field (that fall on adjacent points on the retina) are processed by neurons in adjacent parts of that cortical area. ... Tonotopy (from Greek tono- and topos = place: the place of tones) is the spatial arrangement of where sound is perceived, transmitted, or received. ... Somatotopic arrangement is the maintenance of spatial organisation within the central nervous system. ... The concept of a homunculus (Latin for little man, sometimes spelled homonculus, plural homunculi) is often used to illustrate the functioning of a system. ...


Motor areas

The motor areas are located in both hemispheres of the cortex. They are shaped like a pair of headphones stretching from ear to ear. The motor areas are very closely related to the control of voluntary movements, especially fine fragmented movements performed by the hand. The right half of the motor area controls the left side of the body and vice versa.


Two areas of the cortex are commonly referred to as motor:

  • Primary motor cortex, which executes voluntary movements
  • Supplementary motor areas and premotor cortex, which select voluntary movements.

In addition, motor functions have been described for: The primary motor area is a group of networked cells in mammalian brains that controls movements of specific body parts associated with cell groups in that area of the brain. ...

  • Posterior Parietal Cortex, which guides voluntary movements in space
  • Dorsolateral Prefrontal Cortex, which decides which voluntary movements to make according to higher-order instructions, rules, and self-generated thoughts.

Association areas

Association areas function to produce a meaningful perceptual experience of the world, enable us to interact effectively, and support abstract thinking and language. The parietal, temporal, and occipital lobes - all located in the posterior part of the brain - organise sensory information into a coherent perceptual model of our environment centred on our body image. The frontal lobe or prefrontal association complex is involved in planning actions and movement, as well as abstract thought. Our language abilities are localised to the association areas of the the parietal-temporal-occipital complex, typically in the left hemisphere. Wernicke's area relates to understanding language while Broca's area relates to its use. In psychology and the cognitive sciences, perception is the process of acquiring, interpreting, selecting, and organizing sensory information. ... The parietal lobe is a lobe in the brain. ... The temporal lobes are part of the cerebrum. ... The occipital lobe is the visual processing center of the mammalian brain, containing most of the anatomical region of the visual cortex. ... Body image is a persons perception of his or her physical appearance. ... The frontal lobe is an area in the brain of mammals. ... 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). ... 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. ...


Classification

Based on the differences in lamination the cerebral cortex can be classified into two major groups:

  • Isocortex (homotypical cortex), the part of the cortex with six layers.
  • Allocortex (heterotypical cortex) with variable number of layers, e.g., olfactory cortex and hippocampus.

Auxiliary classes are: Isocortex is the part of the cerebral cortex with a six layer laminar structure. ... Ö“üÅ[[]]→óùÄŒ ... The olfactory system is the sensory system used for olfaction. ... The hippocampus is structurally located inside the medial temporal lobe of the brain. ...

Based on supposed developmental differences the following classification also appears: Proisocortex is an area in the cerebral cortex. ... A Brodmann area is a region in the brain cortex defined in many different species based on its cytoarchitecture. ... 24 - ventral anterior cingulate (area cingularis anterior ventralis). ... // Human Brodmann area 25 (BA25) is an area in the cerebral cortex of the brain and delineated based on its cytoarchitectonic characteristics. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Ö“üÅ[[]]→óùÄŒ ...

In addition, cortex may be classified on the basis of gross topographical conventions into the following: The neocortex (Latin for new bark or new rind) is a part of the brain of mammals. ... The neopallium (Latin for new mantle) is a part of the brain of mammals. ... Archicortex is basically categorized under allocortex. ... The paleocortex is a layer of the cerebral cortex intermediate phylogenetically between the neocortex and archicortex. ...

  • Temporal Cortex
  • Parietal Cortex
  • Frontal Cortex
  • Occipital Cortex

Cortical thickness

With magnetic resonance brain scanners it is possible to get a measure for the thickness of the human cerebral cortex and relate it to other measures. One study has found some positive association between the cortical thickness and intelligence.[3] The history of neuroimaging, began in the early 1900s with a technique called pneumoencephalography. ... For other uses, see Intelligence (disambiguation). ...


See also

A cortical column is a group of neurons in the brain cortex which can be successively penetrated by a probe inserted perpendicularly to the cortical surface, and which have nearly identical receptive fields. ... The frontal lobe is an area in the brain of mammals. ... The limbic system (Latin limbus: border or edge) includes the structures in the human brain involved in emotion, motivation, and emotional association with memory. ... // medulla oblongata medullary pyramids pons paramedian pontine reticular formation fourth ventricle cerebellum cerebellar vermis cerebellar hemispheres anterior lobe posterior lobe flocculonodular lobe cerebellar nuclei fastigial nucleus globose nucleus emboliform nucleus dentate nucleus tectum inferior colliculi superior colliculi mesencephalic duct (cerebral aqueduct, Aqueduct of Sylvius) cerebral peduncle midbrain tegmentum ventral tegmental... A microgyrus is an area of the cerebral cortex that includes only four cortical layers instead of six. ... The occipital lobe is the visual processing center of the mammalian brain, containing most of the anatomical region of the visual cortex. ... The parietal lobe is a lobe in the brain. ... The temporal lobes are part of the cerebrum. ... The human brain as viewed from above, showing the cerebral hemispheres. ... Corticogenesis in a mouse brain. ... // A brain-computer interface (BCI), sometimes called a direct neural interface or a brain-machine interface, is a direct communication pathway between a human or animal brain (or brain cell culture) and an external device. ...

Further reading

  • Kandel, E.R., Schwartz, J. H., and Jessell, T.M. Principles of Neural Science (Fourth Edition). 2000. New York, McGraw Hill. ISBN 0-8385-7701-6.
  • Zigmond, M. J., Bloom, F. E., Landis, S.C., Roberts, J.L, and Squire, L.R. Fundamental Neuroscience. 1999. San Diego, Academic Press. ISBN 0-12-780870-1.

References

  1. ^ P. Rakic (1988). "Specification of cerebral cortical areas". Science 241 (4862): 170–176. doi:10.1126/science.3291116. 
  2. ^ Stephen C. Noctor, Alexander C. Flint, Tamily A. Weissman, Ryan S. Dammerman & Arnold R. Kriegstein (2001). "Neurons derived from radial glial cells establish radial units in neocortex". Nature 409 (6821): 714–720. doi:10.1038/35055553. PMID 11217860. 
  3. ^ Katherine L. Narr, Roger P. Woods, Paul M. Thompson, Philip Szeszko, Delbert Robinson, Teodora Dimtcheva, Mala Gurbani, Arthur W. Toga and Robert M. Bilder (2007). "Relationships between IQ and Regional Cortical Gray Matter Thickness in Healthy Adults". Cerebral Cortex 17 (9): 2163–2171. 
  • Angevine, J. and Sidman, R. 1961. Autoradiographic study of cell migration during histogenesis of cerebral cortex in the mouse. Nature, 192:766-768
  • Creuzfeldt, O. 1995. Cortex Cerebri. Springer-Verlag.
  • Marin-Padilla, M. 2001. Evolución de la estructura de la neocorteza del mamífero: Nueva teoría citoarquitectónica. Rev. Neurol, 33(9):843-853
  • Mountcastle, V. 1997. The columnar organization of the neocortex. Brain, 120:701-722
  • Noctor SC, Flint AC, Weissman TA, Dammerman RS, Kriegstein AR. (2001) Neurons derived from radial glial cells establish radial units in neocortex. "Nature" 409(6821):714-720. PMID 11217860
  • Ogawa, M. et al. 1995. The reeler gene-associated antigen on Cajal-Retzius neurons is a crucial molecule for laminar organization of cortical neurones. Neuron, 14:899-912
  • Rakic, P. 1988. Specification of cerebral cortical areas. Science, 241:170-176
  • Friauf, J. 1991. Changing patterns of synaptic input to subplate and cortical plate during development of visual cortex.
  • Braitenberg, V and Schüz, A 1991. "Anatomy of the Cortex: Statistics and Geometry" NY: Springer-Verlag

Year 1988 (MCMLXXXVIII) was a leap year starting on Friday (link displays 1988 Gregorian calendar). ... Science is the journal of the American Association for the Advancement of Science (AAAS). ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... Nature is a prominent scientific journal, first published on 4 November 1869. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links


  Results from FactBites:
 
Cerebral cortex - Wikipedia, the free encyclopedia (1605 words)
The cerebral cortex is a brain structure in vertebrates.
The surface of the cerebral cortex is folded in large mammals like humans, where more than two thirds of the cortical surface is buried in the grooves, called "sulci".
The senses of vision, audition and touch are served by the primary visual cortex, primary auditory cortex and primary somatosensory cortex.
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