AN OUTLINE OF RECENT ADVANCES IN BIRDSONG NEUROBIOLOGY

Several landmark discoveries have shaped the recent study of brain substrates for birdsong. The failure of deaf birds to reproduce a song from memory lent support for the concept of a song template. An attempt to test this idea resulted in the discovery of lateralization of song control. Search for the brain sites of lateralization and auditory control of voice led to the discovery of the main song control nuclei. Neurophysiological studies have unequivocally shown that auditory information reaches the song control system, but the exact pathway by which the song control system receives auditory inputs needs further investigation. The finding that lesions of the lateral magnocellular nucleus of the anterior neostriatum or area X affect song development in young birds but not the maintenance of song in adults suggested a role of the anterior forebrain pathway to RA in song learning. Another area of research in which much progress has been made concerns the relationships between the vocal and respiratory systems. The archistriatal and midbrain vocal nuclei innervate some of the respiratory centers in the medulla. The old questions of 'mini-breath' during fast singing and independent control of the two sides of the syrinx have been resolved. Finally, comparisons of the vocal and auditory systems between taxa indicate that different groups may use different neural circuits to achieve similar vocal-auditory behavior.