[1] Univ Oxford, Ctr Funct MRI Brain, Oxford OX3 9DU, England
[2] Univ Texas Hlth Sci Ctr San Antonio, Res Imaging Ctr, San Antonio, TX 78229 USA
[3] Yale Univ, Inst Living, Olin Neuropsychiat Res Ctr, New Haven, CT 06106 USA
[4] Inst Pasteur, F-75724 Paris, France
[5] Univ London Imperial Coll Sci Technol & Med, Dept Clin Neurosci, London SW7 2AZ, England