1. J. Lisman is in the Department of Biology and Center for Complex Systems, Brandeis University, Waltham, MA 02254 USA.
2. R. C. Malenka is in the Departments of Psychiatry and Physiology, University of California, San Francisco, CA 94143, USA.
3. R. A. Nicoll is in the Departments of Cellular and Molecular Pharmacology and Physiology, University of California, San Francisco, CA 94143, USA.
4. R. Malinow is at Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.