- Email: [email protected]
Metabolic stress and cerebral grey matter in psychosis
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Methods: Sixteen schizophrenic patients and 16 unrelated healthy controls matched for age, sex, handedness and social class underwent a series of neuropsychological assessments and a brain magnetic resonance imaging (MRI) scan. Neuropsychological function was assessed by administering a battery of tests including tests of: (1) Intelligence, assessed by the Wechsler Adult Intelligence Scale-Revised (WAIS-R); (2) Memory, measured by Russell's (1975) version of the Wechsler Memory Scale (WMS); and (3) Shifting Mental Sets, tested using the Trails B. MRI data were acquired using a single 1.5 Tesla General Electric Signa System. Whole brain volumetric measurements were made on spoiled-gradient images employing MEASURE, a software package that uses stereological principles. Results: In the patient sample, no significant associations were found between performance on any neuropsychological measure and whole brain volume. In the control sample, a positive correlation emerged between full-scale IQ and whole brain w~lume (r=0.48, P=0.02). Conclusion: Normal structure/function relationships change in pathological states.
A.216. METABOLIC CEREBRAL GREY
STRESS AND MATTER IN PSYCHOSIS
M. Marcelis, Ph. Delespaul, P. Woodruff, J. Suckling, P. H o f m a n , J. van Os
Dept. of PsvchiaoT and Neuropsychology, Maastricht University, European Graduate School of Neuroscience, PO Box 616, 6200 MD Maastricht, The Netherlands Background: It has been reported that (i) individuals with schizophrenia have an altered HVA-response to metabolic stress and (ii) that such increased stress sensitivity is associated with reduced cerebral cortical volume (Breier et al., 1993). Method: Patients with psychosis (n = 50), first degree relatives of patients with psychosis (n = 50) and controls without psychosis (n = 50) underwent double-blind administration of either the glucose analog 2-deoxyglucose (2DG), which induces a mild transient hypoglycaemia, or placebo. Plasma HVA was sampled on six occasions after 2DG/placebo administration. Dual-echo coronal MRI scans were analysed using the automated SMART procedure, yielding total grey, white and CSF volumes. Results: Analyses of data pertaining to the first 44 subjects (controls n=6, relatives n=21, patients n=20), yielding an observation frame of 522 HVA measurements, revealed a significant interaction between time (the six measurement occasions) and condition (2DG vs. placebo) in all three groups, indicating an increase in HVA over time in the 2DG condition. The time ×condition interaction was greatest in the patient group (B= 1.34, P<0.001 ), followed by the relatives (B=0.89, P<0.001 ) and controls (B=0.87, P=0.001 ). In the patients, there was a significant negative interaction between time and grey matter volume (B=-0.0064, P=0.007), indicating patient-specific increased sensitivity to metabolic stress with lower grey matter volume (controls: B---0.0006, P=0.85; relatives: B = - 0 . 0 0 0 5 , P=0.76). Conclusion: Patients with psychosis may have altered sensitivity to stress associated with decreased grey matter volume.
Reference Breier et al., Archives of General Psychiatry, 1993, 50, 541 550.
A.217. CORTICAL SHAPE DIFFERENCES BETWEEN SCHIZOPHRENIC SUBJECTS AND NORMALS
A.D. Castellano Smith, P.G. Batchelor, X.A. Chitnis, D.L.G. Hill, T. S h a r m a Radiological Sciences, 5th Floor, Thomas Guy House, Guy's" Hospital, Kings College London, SEI 9RT, United Kingdom There has been much research in recent years concerning the possible morphological differences between the surface of the schizophrenic cerebral cortex and the normal, e.g. 1'2'3. In the work presented here, we critically examine measures of surface shape used in published works relating to schizophrenia and other diseases. We propose a number of new measures of shape, based on convexity, normalised surface area to volume ratios, and measures based on integrals of surface curvatures, and the asymmetry in these measures between left and right hemispheres. We apply this suite of measures to a series of manually segmented schizophrenic and matched normal brain surfaces. The asymmetries in the measures we define, if considered as a multi-variate descriptor of shape, distinguish all of the schizophrenics in our sample from the normals. Interestingly, we find the widely used Gyrification Index less reliable in this regard. We believe that our shape measures may allow a more precise exploration of the probable differences in cortical surface shape between schizophrenics and normals, and propose that our multi-variate approach be used in preference to any single measure of gyrification. A larger study is in progress.
References 1. J.R. DeQuardo et al., Psychiatry Research: Neuroimaging, 67:81 95 (1996). 2. J.J. Kulynych et al., Biol Psychiatry, 41:995 999 (1997). 3. M.D. Stefan et al., Schizophrenia Research. 24:157 (1997).
A.218. CORTICAL SURFACE ASYMMETRIES AND SULCAL SHAPE VARIABILITY lN SCHIZOPHRENIA K a t h e r i n e L. N a r r 1, T o n m o y S h a r m a 2, Paul T h o m p s o n ~, J a c o b Moussai, A r t h u r W. Toga 1
ILaboratory of Neuro Imaging. Division of Brain Mapping, Department of Neurology, UCLA School of Medicine, Los Angeles, USA, 2Section of Cognitive Psychopharmacology, Institute o[ Psvchiatrv, London, UK Neuroanatomic abnormalities are characteristic in schizophrenic populations. Cerebral anomalies include alterations in sulco-gyral patterns 1 and cerebral asymmetries 2'3. High-
Methods: Sixteen schizophrenic patients and 16 unrelated healthy controls matched for age, sex, handedness and social class underwent a series of neuropsychological assessments and a brain magnetic resonance imaging (MRI) scan. Neuropsychological function was assessed by administering a battery of tests including tests of: (1) Intelligence, assessed by the Wechsler Adult Intelligence Scale-Revised (WAIS-R); (2) Memory, measured by Russell's (1975) version of the Wechsler Memory Scale (WMS); and (3) Shifting Mental Sets, tested using the Trails B. MRI data were acquired using a single 1.5 Tesla General Electric Signa System. Whole brain volumetric measurements were made on spoiled-gradient images employing MEASURE, a software package that uses stereological principles. Results: In the patient sample, no significant associations were found between performance on any neuropsychological measure and whole brain volume. In the control sample, a positive correlation emerged between full-scale IQ and whole brain w~lume (r=0.48, P=0.02). Conclusion: Normal structure/function relationships change in pathological states.
A.216. METABOLIC CEREBRAL GREY
STRESS AND MATTER IN PSYCHOSIS
M. Marcelis, Ph. Delespaul, P. Woodruff, J. Suckling, P. H o f m a n , J. van Os
Dept. of PsvchiaoT and Neuropsychology, Maastricht University, European Graduate School of Neuroscience, PO Box 616, 6200 MD Maastricht, The Netherlands Background: It has been reported that (i) individuals with schizophrenia have an altered HVA-response to metabolic stress and (ii) that such increased stress sensitivity is associated with reduced cerebral cortical volume (Breier et al., 1993). Method: Patients with psychosis (n = 50), first degree relatives of patients with psychosis (n = 50) and controls without psychosis (n = 50) underwent double-blind administration of either the glucose analog 2-deoxyglucose (2DG), which induces a mild transient hypoglycaemia, or placebo. Plasma HVA was sampled on six occasions after 2DG/placebo administration. Dual-echo coronal MRI scans were analysed using the automated SMART procedure, yielding total grey, white and CSF volumes. Results: Analyses of data pertaining to the first 44 subjects (controls n=6, relatives n=21, patients n=20), yielding an observation frame of 522 HVA measurements, revealed a significant interaction between time (the six measurement occasions) and condition (2DG vs. placebo) in all three groups, indicating an increase in HVA over time in the 2DG condition. The time ×condition interaction was greatest in the patient group (B= 1.34, P<0.001 ), followed by the relatives (B=0.89, P<0.001 ) and controls (B=0.87, P=0.001 ). In the patients, there was a significant negative interaction between time and grey matter volume (B=-0.0064, P=0.007), indicating patient-specific increased sensitivity to metabolic stress with lower grey matter volume (controls: B---0.0006, P=0.85; relatives: B = - 0 . 0 0 0 5 , P=0.76). Conclusion: Patients with psychosis may have altered sensitivity to stress associated with decreased grey matter volume.
Reference Breier et al., Archives of General Psychiatry, 1993, 50, 541 550.
A.217. CORTICAL SHAPE DIFFERENCES BETWEEN SCHIZOPHRENIC SUBJECTS AND NORMALS
A.D. Castellano Smith, P.G. Batchelor, X.A. Chitnis, D.L.G. Hill, T. S h a r m a Radiological Sciences, 5th Floor, Thomas Guy House, Guy's" Hospital, Kings College London, SEI 9RT, United Kingdom There has been much research in recent years concerning the possible morphological differences between the surface of the schizophrenic cerebral cortex and the normal, e.g. 1'2'3. In the work presented here, we critically examine measures of surface shape used in published works relating to schizophrenia and other diseases. We propose a number of new measures of shape, based on convexity, normalised surface area to volume ratios, and measures based on integrals of surface curvatures, and the asymmetry in these measures between left and right hemispheres. We apply this suite of measures to a series of manually segmented schizophrenic and matched normal brain surfaces. The asymmetries in the measures we define, if considered as a multi-variate descriptor of shape, distinguish all of the schizophrenics in our sample from the normals. Interestingly, we find the widely used Gyrification Index less reliable in this regard. We believe that our shape measures may allow a more precise exploration of the probable differences in cortical surface shape between schizophrenics and normals, and propose that our multi-variate approach be used in preference to any single measure of gyrification. A larger study is in progress.
References 1. J.R. DeQuardo et al., Psychiatry Research: Neuroimaging, 67:81 95 (1996). 2. J.J. Kulynych et al., Biol Psychiatry, 41:995 999 (1997). 3. M.D. Stefan et al., Schizophrenia Research. 24:157 (1997).
A.218. CORTICAL SURFACE ASYMMETRIES AND SULCAL SHAPE VARIABILITY lN SCHIZOPHRENIA K a t h e r i n e L. N a r r 1, T o n m o y S h a r m a 2, Paul T h o m p s o n ~, J a c o b Moussai, A r t h u r W. Toga 1
ILaboratory of Neuro Imaging. Division of Brain Mapping, Department of Neurology, UCLA School of Medicine, Los Angeles, USA, 2Section of Cognitive Psychopharmacology, Institute o[ Psvchiatrv, London, UK Neuroanatomic abnormalities are characteristic in schizophrenic populations. Cerebral anomalies include alterations in sulco-gyral patterns 1 and cerebral asymmetries 2'3. High-