An Evolutionary Approach to the Investigation of PsychoneuroEndocrine Functions

Abstract

Evolutionary considerations are helpful in the approach to brain and behavior investigations, including those on neuroendocrine mechanisms. As diagrammed in Fig. 1, the primate forebrain evolves in hierarchic fashion along the lines of three basic patterns which, for purposes of discussion, I refer to as reptilian, paleo-mammalian, and neomammalian (MacLean 1962, 1964, 1967). Although markedly unlike in chemistry and structure, the three cerebrotypes establish extensive interconnections and function together as a triune brain (MacLean 1970a). Yet there is evidence that each is capable of operating somewhat independently.