[1] Univ Lisbon, Lisbon Sch Hlth Technol, Polytech Inst Lisbon, Inst Biophys & Biomed Engn, P-1699 Lisbon, Portugal
[2] Univ Lisbon, Fac Sci, Inst Biophys & Biomed Engn, P-1699 Lisbon, Portugal
[3] Univ London Imperial Coll Sci Technol & Med, Div Brain Sci, Dept Med, Ctr Neuropsychopharmacol, London, England
[4] Kings Coll London, Inst Psychiat, Ctr Neuroimaging Sci, London WC2R 2LS, England
[5] Forschungszentrum Julich, Inst Neurosci & Med 4, Julich, Germany