Journal of Neuroscience, Vol 15, 6281-6286, Copyright © 1995 by Society for Neuroscience
Brain space for learned song in birds develops independently of song learning
EA Brenowitz, K Lent and DE Kroodsma
Department of Psychology, University of Washington, Seattle 98195, USA.
In numerous species of birds, individuals or species that sing larger
numbers of song types have larger song control nuclei in their brains. The
direction of the cause and effect relationship between the complexity of
song behavior and brain space is unknown, however. The hypothesis that
birds that learn large song repertoires develop large song nuclei was
therefore tested with a songbird, the marsh wren (Cistothorus palustris).
Males were hand-reared and tutored in the laboratory with either small (n =
8 males heard 5 song types) or large (n = 8 males heard 45 song types)
repertoires. When the birds were adults, the number of song types each male
sang was first determined, and then the volume and certain cellular
attributes of the song nuclei HVC and RA were measured. The two groups of
wrens showed large behavioral differences in the size of their learned song
repertoires, but did not differ in either the volumes of HVC and RA or in
neuronal size, number, or density within these nuclei. These results
suggest that the relationship between behavioral song complexity and brain
space found in this and other species develops largely independently of
early song learning experience and the later production of those songs.