1Psychiatric Neuroimaging Research Group and Nuclear Magnetic Resonance Center, Massachusetts General Hospital, Harvard Medical School, 13th St., Bldg 149, CNY-9, Charlestown, MA 02129
2Brigham Behavioral Neurology Group, Department of Neurology, Brigham and Women's Hospital, Boston, MA 02115
3Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612
4Department of Psychology, Tufts University, Medford, MA 02155, USA
5ARC-Aging Research Center, Karolinska Institute and Stockholm University, Stockholm, Sweden
Received 3 1 January 2002 accepted 1 8 February 2002
CA,1Corresponding Author and Address: Psychiatric Neuroimaging Research Group and Nuclear Magnetic Resonance Center, Massachusetts General Hospital, Harvard Medical School, 13th St., Bldg 149, CNY-9, Charlestown, MA 02129
