SEXUAL-DIFFERENTIATION OF AVIAN BRAIN AND BEHAVIOR - CURRENT VIEWS ONGONADAL HORMONE-DEPENDENT AND INDEPENDENT MECHANISMS

Gonadal hormones are known to act during development to establish perm anent sex differences in the anatomy and function of the vertebrate br ain. They also act on the adult brain to activate reproductive behavio rs. However, there are wide gaps in our understanding of how sexually dimorphic neural circuits translate into sex differences in behavior a nd other CNS functions. Moreover, not all sexually dimorphic propertie s of the adult brain can be attributed to known effects of gonadal hor mones during development or adulthood, and factors other than gonadal steroids may contribute to these sex differences. This paper reviews s exual differentiation and the role of gonadal steroids and non-gonadal factors on sexually dimorphic development of the avian brain.