 Majorchronic medical conditions. History of head injury resulting in prolonged loss of consciousness andor neurological sequelae. History of seizures. History of stroke Prior neurosurgical procedure. Metal in the body, metal injury to the eyes. Implanted pacemaker, medication pump, vagal stimulator, deep brain stimulator, TENS unit, or ventriculo-peritoneal shunt. Pregnancy; breastfeeding or nursing Claustrophobia Weight 350 lbs. 