Paleocortex

The paleocortex (or paleopallium) and the archicortex (or the archipallium) of the cerebral cortex together constitute the mammalian allocortex or the heterogenetic cortex. The distinction for what is called neocortex or isocortex, which comprises most of the human brain (about 90%), is made from the number of cellular layers that the structure comprises. Neocortical tissue comprises six distinct cell layers, not seen in paleocortical tissues either in adult or developing stage.

In humans the paleocortex is exemplified in the olfactory cortex. For most vertebrates, the olfactory bulb is the main feature of the paleocortex, even though the division is virtually unused outside of a mammalian context.

Locations

Paleocortex is present in the parahippocampal gyrus, olfactory bulb, accessory olfactory bulb, olfactory tubercle, piriform cortex, periamygdalar area, anterior olfactory nucleus, anterior perforated substance, and prepyriform area.