1. J. M. Barrie [] is in the Department of Molecular and Cell Biology,[] Neurobiology Division, University of California, Berkeley,[] CA 94720-3200, USA..
2. D. E. Presti is in the Department of Molecular and Cell Biology, Neurobiology Division, University of California, Berkeley, CA 94720-3200, USA, and with the Veteran's Affairs Medical Center, San Francisco, CA 94121, USA.