Proisocortex or pro-isocortex is one of two subtypes of
cortical areas in the areas belonging to the
neocortex
The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian cerebral cortex involved in higher-order brain functions such as sensory perception, cognition, generation of motor commands, sp ...
. 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
The allocortex or heterogenetic cortex, and neocortex are the two types of cerebral cortex in the brain. The allocortex is the much smaller area of cortex taking up just 10 %, the neocortex takes up the remaining 90 %. It is characterized by havi ...
and proisocortex). The histological structure of proisocortex is also transitional between true isocortex and either
peripaleocortex Peripaleocortex is one of two subtypes of periallocortex, the other being periarchicortex. Peripaleocortex is formed at borders between isocortex (neocortex) and paleocortex (a subtype of allocortex). It shows slow histological transition from the ...
or
periarchicortex Periarchicortex is one of two subtypes of periallocortex, the other being peripaleocortex. It is formed at borders between archicortex (a subtype of allocortex) and isocortex and shows slow histological transition from the four-layered structure ty ...
, depending on with which subtype of periallocortex the given proisocortical area borders.
Proisocortex is found in the
cingulate cortex
The cingulate cortex is a part of the brain situated in the medial aspect of the cerebral cortex. The cingulate cortex includes the entire cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the ci ...
(part of the
limbic system
The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''Ps ...
), in
Brodmann's areas
24,
25,
30 and
32, the
insula and
parahippocampal gyrus
The parahippocampal gyrus (or hippocampal gyrus') is a grey matter cortical region of the brain that surrounds the hippocampus and is part of the limbic system. The region plays an important role in memory encoding and retrieval. It has been inv ...
.
The transitional cortical areas from isocortical side (i.e. proisocortex) and from allocortical side (i.e. periarchicortex and peripaleocortex) together are called
mesocortex Mesocortex (also called juxtallocortex) is the transitional areas of the cerebral cortex, formed at borders between true isocortex and true allocortex (either paleocortex or archicortex). Parts of mesocortex that lie closer to the true isocortex an ...
. The mesocortex is essentially the same as
paralimbic cortex
The paralimbic cortex is an area of three-layered Cerebral cortex, cortex that includes the following regions: the piriform cortex, entorhinal cortex, the parahippocampal cortex on the Anatomical terms of location#Left and right (lateral), and med ...
, 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
Cytoarchitecture (Greek '' κύτος''= "cell" + '' ἀρχιτεκτονική''= "architecture"), also known as cytoarchitectonics, is the study of the cellular composition of the central nervous system's tissues under the microscope. Cytoarchi ...
and histology, while the paralimbic cortex is an anatomical designation, meaning cortical areas near subcortical limbic structures.
References
External links
Proisocortex BrainInfo.
Cerebral cortex
{{Cortex types