1. Veterans Affairs Healthcare System, San Diego, California 92161;,
2. Department of Psychiatry, University of California, San Diego, La Jolla, California 92093;
3. Department of Neurosciences, University of California, San Diego, La Jolla, California 92093;
4. Department of Psychology, University of California, San Diego, La Jolla, California 92093;
5. Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, Maryland 21205;