- Controls: illiteracy, deficit on MMSE (Mini-Mental State Examination), visual, auditory or motor deficit, history of brain disease or psychiatric illness (schizophrenia or other psychosis) or ongoing psychiatric illness (depression or other) currently requiring treatment or requiring a stay > 2 days in psychiatry unit or anxiety requiring more than one medication at the present time, alcoholism, opiate or illicit drug use < 3 months, ongoing antidepressant or antiepileptic treatment, recent anxiolytic or hypnotic treatment, general anaesthesia < 3 months, history of heart surgery with cardiopulmonary bypass