What are we learning from the comparative studies of other mammalian brains?
One of the most striking findings is that many brain features tend to be highly consistent across all mammals. The number of cortical areas varies across the different mammalian orders, reflecting a very early evolutionary divergence among them. Multiple association sensory cortices, especially within the visual system, were gained independently in the different orders, with primates exhibiting the highest number of such regions. In contrast, the basic organization of the various sensory and motor system pathways is shared not only across all mammals but across most other vertebrate groups as well. One of the most important findings of the last several decades of comparative research is the realization that birds, like mammals, have a very large pallial component in their forebrains. In mammals, most of the pallium is neocortex, which carries out our high-level sensory and cognitive functions, but the cellular architecture of the avian pallium is different from that cortex in some resp
