An Avian Basal Ganglia Pathway Essential for Vocal Learning Forms a Closed Topographic Loop

This work was supported by National Institutes of Health Grant MH 56646 and by National Science Foundation Grant IBN 9817889 (D.J.P.). We thank Drs. M. P. Nusbaum and R. J. Balice-Gordon for helpful comments on this manuscript.

Correspondence should be addressed to David J. Perkel, Departments of Zoology and Otolaryngology, University of Washington, Box 356515, 1959 Northeast Pacific Street, Seattle, WA 98195-6515. E-mail:perkel{at}u.washington.edu.

M. Luo's present address: Department of Neurobiology, Duke University, Howard Hughes Medical Institute, Durham, NC 27710.