Recent findings on the development of dimorphic anatomy in the avian song system

Much current research in neuroendocrinology concerns how endocrine information acts on the brain. For example, what processes are used early in life to transduce sex differences in gonadal steroids into structural dimorphisms within the brain? Or, to what extent are the actions of steroids on the developing nervous system unique events and to what extent are they a continuing part of the interplay between the endocrine and the central nervous system? The avian song system has proven to be a very useful model system in which to study these issues. Recent research from my laboratory on the development of sex differences in brain structure and on steroid-related adult plasticity is reviewed below. This review is quite focussed. More general reviews of research on the song system can be found in Arnold ('89), DeVoogd ('86), Konishi ('85), and Nottebohm ('88).