Schizophrenia
toOL PSVemATaV X990;27:41A-179A
109A
150 LEFT STRIATO-PALLIDAL HYPERACTIVITY AND RIGHT-
SIDED HEMI-NEGLECT: AN INTEGRATED MODEL OF MULTILEVELED PATHOLOGY IN SCHIZOPHRENIA
T.S. Early, M.D., M.I. Posner, Ph.D., E.M. Reiman, M.D. Washington Universiiy School of Medicine, St. Louis, MO 63110. Previous work in our laboratory has demonstrated abnormally increased relative cerebral blood flow in a group of l0 neuroleptic-naive schizophrenic patients compared with 20 controls (p <: 0.0002 overall by ANOVA). We have also recently observed that schizophrenic patients have difficulty shifting attention to the right visual field, a very subtle form of hemi-neglect (p < 0.0002). Attempts to relate these two findings have resulted in a theory of relating many of the manifestations of schizophrenia to impaired function of a loop in the left hemi-sphere that includes anterior cingulate gyms, ventral striatum, ventral pallidum, and the mediodorsal nucleus of the thalamus. Striato-pallidal hyperactivity and henri-neglect are seen after lesions, such as unilateral dopaminergic denervation or frontal cortex ablations. This model can potentially account for other findings of hemi-neglect in schizophrenia, the association between left-sided temporal lobe epilepsy and psychosis, eye tracking abnormalities, and the beneficial effects of direct dopaminergic agonists on the positive symptoms of psychosis. Findings of left hemispheric dysfunctions may represent a "hemi-neglect of higher cognitive functions." Finally, the model suggests reasons for some of the phenomenologicai symptoms experienced by schizophrenic patients and suggests further testable approaches to understanding this disorder.
151 APOMORPHINE EFFECTS ON BRAIN METABOLISM IN
NEUROLEPTIC-NAIVE, FIRST EPISODE SCHIZOPHRENICS AND NORMAL CONTROLS J.M. Cleghorn, M.D., H. Szechtman, E.S. Garnett, G.M. Brown Department of Psychiatry, McMaster University, Hamilton, Ontario, Canada L8N 37.5. We wished to determine whether DSM-lll schizophrenics never medicated and in a psychotic episode (n = 11) when compared with normal controls (n = 8) would respond differently to the dopamine-agonist apomorphine (APO) in brain regions implicated in schizophrenia, i.e., striatum, temporal and prefrontal cortex. APO, 0.75 mg/70 kg (weight adjusted), and saline were administered in balanced order 20 min ~SFdeoxyglucose, S mCi, and glucose uptake in the above brain regions was measured by means of positron emission tomography on two o~'easions within 1 week. Striatal-relative glucose metabolism decreased with APO in schizophrenics (Fl.lO -- 6.62, p - 0.028) but not in controls. Superior temporal-relative glucose metabolism decreased in schizophrenics (FLmo = 12.02, p = 0.006) and did not in controls. Frontal glucose metabolism was unchanged with APO in schizophrenics, but in controls there was a significant bilateral increase in a caudal frontal area that includes Broca's region (FL7 = 9.82, p = 0.017).
152 MRI CORRELATES OF NEUROPSYCHOLOGICAL
PERFORMANCE IN SCHIZOPHRENIA Robert Bornstein, Ph.D., Steven Schwarzkopf, M.D., Stephen Olson, M.D., Jeffrey Coffman, M.D., Henry Nasrallah, M.D. Department of Psychiatry, Ohio State University, Columbus, OH 43210. This study examined relations between neuropsychological performance and MRI measurements in a sample of schizophrenic patients. 55 patients meeting DSM-III criteria for schizophrenia, primarly outpatients, were included. Subjects received an MRI and a neuropsychological test battery. There were gender differences on several neuropsychological and MRI measurements. Drug level was correlated with MRI and neuropsychological measurements. Partial correlations were computed among the male subjects to reduce