The purpose of this work is to investigate the role of the frontal lobe, and its connections for cognition in health and in neuropsychiatric diseases, particularly schizophrenia. Regional cerebral blood flow (rCBF) will be measured with oxygen-15 water positron emission tomography (PET) while subjects are either at rest or are performing a variety of neuropsychological tests. Some of these tests involve cognitive operations that are posited to depend upon the frontal cortex, such as the use of working memory for abstract reasoning and problem solving, formation and maintenance of conceptual sets, set shifting, sequencing, and delayed response; others control for nonspecific sensory and motor aspects of these measurements or are contrast conditions posited to depend on other brain regions. Interactions between regional activation, cognitive behavior, and neuropharmacology will be assessed by measuring cognitively-related rCBF during treatment with drugs that may affect frontal lobe physiology. Hypotheses about genetic determinants of these relationships will also be tested by comparing rCBF measures across individuals harboring different genotypes (detemined through protocol 95-M-0150).
The purpose of this study is to use brain imaging technology to investigate the role of the frontal lobe of the brain in the thinking of individuals with schizophrenia and other neuropsychiatric disorders and healthy volunteers.~Participants in this study will undergo a positron emission tomography (PET) scan of the brain while performing neuropsychological tests. Some of the tests involve cognitive operations that depend upon the frontal cortex. Interactions between frontal lobe activation, cognitive behavior, and neuropharmacology will be assessed by measuring regional cerebral blood flow (rCBF) during treatment with drugs that may affect frontal lobe physiology.