Birdsong as a Model in Which to Study Brain Processes Related to Learning

The last fifteen years have yielded an ever increasing amount of information about brain pathways for song control in songbirds. I review here aspects of this work which suggest that the size of brain networks for song control may limit how much can be learned. In addition, sustained learning in adulthood may relate to plasma levels of gonadal hormones and to the replacement of dendrites, synapses and neurons. Mechanisms involved in this pathway "rejuvenation" may be similar to mechanisms for brain self-repair.