1Animal Imaging and Technology Core (AIT), Center for Biomedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 2Service of General Psychiatry, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland, 3Unit for Research in Schizophrenia, Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital (CHUV), Lausanne, Switzerland, 49. Division of clinical pharmacology, Lausanne University Hospital (CHUV), Lausanne, Switzerland, 5Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 6Department of Radiology, University of Geneva, Geneva, Switzerland, 7Department of Radiology, University of Lausanne, Lausanne, Switzerland, 82. Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany