 The neocortex is the newest part of the cerebral cortex to evolve (hence the prefix "neo"); the other parts of the cerebral cortex are the paleocortex and archicortex, collectively known as the allocortex.In humans, 90% of the cerebral cortex is neocortex.Researchers have argued that consciousness in mammals arises in the neocortex, and therefore cannot arise in animals which lack a neocortex.