Acute D2 Receptor Blockade Induced Neuronal Network Changes in Human Volunteers

Inclusion Criteria: * Between 18 and 60 years of age * Subject is competent to provide informed consent Exclusion Criteria: * Mini Mental Status Exam is less than 28 * Past or current history of any psychotic illness in the subject or in first degree family members * Self report of illicit drug use (except marijuana) in the past. Use of marijuana during the last 3 month... * Any use of antipsychotic in the past. * Any neuro-anatomical lesions on previous brain imaging * Any use of D2 receptor blocking agent (such as antiemetics) in the last two weeks. * Any use of any psychotropic medications (SSRI, mood stabilizers, benzodiazepines, stimulants) in the last month. * MRI contraindications * Any cardiovascular or cerebrovascular diseases or conditions that predispose patients to hypotension (eg. dehydration, hypovolemia, antihypertensive medication) * Subjects with diabetes mellitus, metabolic syndrome, hepatic or renal impairment, seizure disorder and any neurological disorder * QTc interval longer than 450 ms for male and 470 ms for female * Subjects who used any medications in the last two weeks (to avoid any possible drug-drug interactions) * Pregnancy * Individuals who are illiterate and/or visually impaired