1. G. S. Berns, Department of Psychiatry, University of Pittsburgh Medical Center, Western Psychiatric Institute and Clinic, 3811 O’Hara Street, Pittsburgh, PA 15213, USA.
2. J. D. Cohen, Department of Psychology, Carnegie Mellon University, and Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
3. M. A. Mintun, Departments of Radiology and Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.