Cytoarchitectonic and Connectional Organization of the Lacertilian Telencephalon with Comments on Vertebrate Forebrain Evolution

Abstract

Two assumptions regarding nonmammalian vertebrates have long been held to be true. The first of these is that nonmammals, as opposed to mammals, behave in stereotyped ways and have little capacity to modify their behavior through learning. The second assumption is that nonmammals are “lower” vertebrates, representing evolutionary stages that gave rise to the “higher” vertebrates, i.e., mammals. Both of these assumptions suggest that the brains of nonmammalian vertebrates (1) are much more simply organized than the brains of mammals and (2) lack any structures which would be comparable to the “higher” (different usage than above but not easily definable) centers of mammalian brains, such as the cerebral neocortex. Thus there would seem to be little reason to study the organization of nonmammalian brains other than out of historical, evolutionary interest.