Proisocortex

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Proisocortex or pro-isocortex is one of two subtypes of cortical areas in the areas belonging to the neocortex. The other subtype is termed the true isocortex. Proisocortical areas are transitional areas placed between areas of true isocortex and areas of periallocortex (which themselves are transitional between "true" allocortex and proisocortex). The histological structure of proisocortex is also transitional between true isocortex and either peripaleocortex or periarchicortex, depending on with which subtype of periallocortex the given proisocortical area borders. [1]

Proisocortex is found in the cingulate cortex (part of the limbic system), in Brodmann's areas 24, 25, 30 and 32, the insula and parahippocampal gyrus. [1]

The transitional cortical areas from isocortical side (i.e. proisocortex) and from allocortical side (i.e. periarchicortex and peripaleocortex) together are called mesocortex. The mesocortex is essentially the same as paralimbic cortex, as all mesocortical transitional areas are found exclusively in paralimbic region, and vice versa - all the paralimbic cortex is mesocortical in its nature (embryonic and phylogenetic origins) and in its histology. But the term "mesocortex" represents a different concept from the term "paralimbic cortex". The mesocortex is distinguished from other cortical areas based on cytoarchitectonics and histology, while the paralimbic cortex is an anatomical designation, meaning cortical areas near subcortical limbic structures. [2]

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<span class="mw-page-title-main">Brodmann area</span> Region of the brain

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Mesocortex is the transitional areas of the cerebral cortex, formed at borders between true isocortex and true allocortex. Parts of mesocortex that lie closer to the true isocortex and have more resemblance to the isocortex in their cytoarchitectonics and histology, are called proisocortex. Parts of mesocortex that lie closer to the true allocortex and have more resemblance to the allocortex in their cytoarchitectonics and histology, are called periallocortex.

Periallocortex is one of three subtypes of allocortex, the other two subtypes being paleocortex and archicortex. The periallocortex is formed at transition areas where any of the other two subtypes of allocortex borders with the neocortex.

Peripaleocortex is one of two subtypes of periallocortex, the other being periarchicortex. Peripaleocortex is formed at borders between isocortex (neocortex) and paleocortex. It shows slow histological transition from the three-layered structure characteristic of paleocortex to the typical six-layered structure characteristic of isocortex. The main peripaleocortex area is anterior insular cortex.

Periarchicortex is one of two subtypes of periallocortex, the other being peripaleocortex. It is formed at borders between archicortex and isocortex and shows slow histological transition from the four-layered structure typical for archicortex to the six-layered structure typical for isocortex.

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References

  1. 1 2 "Proisocortex". BrainInfo. University of Washington. Retrieved 13 October 2017.
  2. "Mesocortex". BrainInfo. University of Washington. Retrieved 13 October 2017.