Allocortex

The allocortex (from Latin allo-, meaning other, and cortex, meaning bark or crust), or heterogenetic cortex, is one of the two types of <a href="/facts/Cerebral_cortex/GpXosGHP">cerebral cortex</a> in the <a href="/facts/Brain/EKla9NkJ">brain</a>, together with the <a href="/facts/Neocortex/YEVjPgGK">neocortex</a>. In the <a href="/facts/Human_brain/qfSwSB8K">human brain</a>, the allocortex is the much smaller area of cortex taking up just 10%; the neocortex takes up the remaining 90%. It is characterized by having just three cortical layers (one main neural layer), in contrast with the six <a href="/facts/Cortical_layers/GpXosGHP">cortical layers</a> of the neocortex. There are three subtypes of allocortex: the <a href="/facts/Paleocortex/M8WUyfAw">paleocortex</a>, the <a href="/facts/Archicortex/5BNxHhpt">archicortex</a>, and the <a href="/facts/Periallocortex/x6E4S02n">periallocortex</a>—a transitional zone between the neocortex and the allocortex.
The specific regions of the brain usually described as belonging to the allocortex are the <a href="/facts/Olfactory_system/MD48Kz6E">olfactory system</a> and the <a href="/facts/Hippocampus/X7CqbP8X">hippocampus</a>.
Allocortex is termed heterogenetic cortex, because during development it never has the six-layered architecture of homogenetic neocortex. It differs from <a href="/facts/Heterotypic_cortex/p8optV00">heterotypic cortex</a>, a type of cerebral cortex, which during prenatal development, passes through a six-layered stage to have fewer layers, such as the <a href="/facts/Agranular_cortex/2L83wIm1">agranular cortex</a> such as <a href="/facts/Brodmann_area_4/UDRmADF4">Brodmann area 4</a> that lacks <a href="/facts/Granule_cell/waE5b3pU">granule cells</a>.

Allocortex open-in-new

Allocortex