THE ORGANIZATION OF NEOCORTEX IN MAMMALS - ARE SPECIES-DIFFERENCES REALLY SO DIFFERENT

By examining a variety of mammals, it is possible to determine common features of cortical organization, and from these infer homologies acr oss species. Such analysis also enables differences in the organizatio n of the neocortex to be identified. Species differ in the amount of c ortex that is devoted to a particular sensory system, in the size and configuration of a cortical field, in the number of cortical fields, a nd in the pattern of connections of homologous fields. It is suggested that the plan of organization that is retained is the result of homol ogous developmental events, and that modifications to this plan are ge nerated by a limited set of mechanisms. These types of changes to the common network might account for the sensory and behavioural diversity that is observed in extant mammals.