Paleocortex


In anatomy of animals, the paleocortex, or paleopallium, is a region within the telencephalon in the brain which is older in an evolutionary sense than the archicortex and the neocortex.
The paleocortex and the archicortex of the cerebral cortex together constitute the allocortex or the heterogenetic cortex. The distinction for what is called neocortex or isocortex, which comprises most of the human brain, 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.
Paleocortex is also defined as a type of cortical tissue that consists of three cortical laminae. In comparison, the neocortex has six layers and the archicortex has three or four layers. Paleocortex, along with archicortex and periallocortex, is a type of allocortex. Because the number of laminae that compose a type of cortical tissue seems to be directly proportional to both the information-processing capabilities of that tissue and its phylogenetic age, paleocortex is thought to be an intermediate between neocortex and archicortex in both aspects.

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.

Parts of the paleocortex