1. Center for Scientific Computation in Imaging and Electrical and Computer Engineering Department, University of California at San Diego, La Jolla, CA 92093, U.S.A.
2. Division of Experimental Therapeutics, Department of Psychiatry, Columbia University, New York, NY 10032, and Schizophrenia Research Division, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, U.S.A.
3. Laureate Institute for Brain Research, Tulsa, OK 74136-3326, U.S.A.
4. Center for Scientific Computation in Imaging and Department of Radiology, University of California at San Diego, La Jolla, CA 92093, and VA San Diego Healthcare System, San Diego, CA 92161, U.S.A.