Comparative Brain Anatomy

The focus will be on what we now know and what we want to know about the functional organization of the human brain and especially human neocortex. We know that humans have the largest brain and more neocortex of all primates, and likely the most neurons in neocortex, which constitutes 80% of our brain. This large cortex is divided into more areas (the organs of cortex) than in any other primate (about 200 per hemisphere), with greater functional and anatomical specializations than any other mammal. We have more extensive developmental and adult plasticity of neocortex and neocortical systems than in other mammals, including systems for memory, that allow us to learn and master specific spoken and written languages, retain vast amounts of cultural information, and recognize thousands of individuals, as well as perhaps, species of birds or kinds of cars. We need to know more fully how human cortex is divided into areas, more precisely what defines each area, how areas are divided into two or more classes of functional modules, how areas interact cortically and subcortically within functional networks, and how networks interact. Importantly, we need to know from comparative studies, how the human brain evolved from ancestors with less complex brains, and how the complexity of human brain emerges and varies in pre and post-natal development.