1. Department of Psychiatry; University of Puerto Rico School of Medicine; San Juan Puerto Rico
2. Department of Psychology; University of Pennsylvania; Philadelphia Pennsylvania
3. Centre for Neuroscience Studies; Queen's University; Kingston Ontario
4. Neurosciences Graduate Training Program; Stanford University; Stanford California
5. Neuroimaging Research Branch; National Institute on Drug Abuse; Intramural Research Program; National Institutes of Health; Baltimore Maryland
6. Department of Psychology; Temple University; Philadelphia Pennsylvania