1 From the Departments of Psychiatry and Psychology, McGill University; the Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University; the Center for Studies in Behavioral Neurobiology, Concordia University; and the Research Unit on Children's Psychosocial Maladjustment, Université de Montréal, Montreal, Que., Canada marco.leyton@mcgill.ca.