1. Department of Neurology, University of California, and Neurology Service, Veterans Administration (VA) Medical Center, San Francisco, CA 94121.
2. Departments of Neurology and Physiology, University of California, and Neurology Service, VA Medical Center, San Francisco, CA 94121.
3. Department of Molecular Oncology, Roche Institute of Molecular Biology, Roche Research Center, Nutley, NJ 07110.