Frontotemporal cerebral blood flow change during executive and declarative memory tasks in schizophrenia: A positron emission tomography study.

Abstract

Schizophrenia affects prefrontal and temporal-limbic networks. These regions were examined by contrasting regional cerebral blood flow (rCBF) during executive (Wisconsin Card Sorting Test [WCST]), and declarative memory tasks (Paired Associate Recognition Test [PART]). The tasks, and a resting baseline, were administered to 15 patients with schizophrenia and 15 healthy controls during 10 min positron emission tomography 15 O-water measures of rCBF. Patients were worse on both tasks. Controls activated inferior frontal, occipitotemporal, and temporal pole regions for both tasks. Similar results were obtained for controls matched to level of patient performance. Patients showed no activation of hypothesized regions during the WCST and activated the dorsolateral prefrontal cortex during the PART. On the PART, occipitotemporal activation correlated with better performance for controls only. Better WCST performance correlated with CBF increase in prefrontal regions for controls and in the parahippocampal gyrus for patients. Results suggest that schizophrenia may involve a breakdown in the integration of a frontotemporal network that is responsive to executive and declarative memory demands in healthy individuals.Schizophrenia was previously thought of primarily as a frontal lobe disorder. Central to this model were neuropsychological results of impaired Wisconsin Card Sorting Test (WCST; Berg, 1948;Grant & Berg, 1948) performance (Goldberg, Weinberger, Berman, Pliskin, & Podd, 1987) and cerebral blood flow (CBF) findings of "hypofrontality" at rest (Ingvar & Franzen, 1974) and in response to WCST task demands (Weinberger, Berman, & Zee, 1986). An alternative model proposed that schizophrenia primarily affects temporal lobe function. Support for this theory included neuropsychological results of differentially impaired learning and memory (Saykin et al., 1991), functional imaging evidence of resting left temporal lobe hypermetabolism , and atypical midtemporal CBF asymmetries in response to memory task demands (Gur, Jaggi, Shtasel, Ragland, & Gur, 1994).Copyright 1998 by the American Psychological Association, Inc.Correspondence concerning this article should be addressed to: J. Daniel Ragland, 10th Floor Gates Building/HUP, Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania 19104. ragland@bblmail.psycha.upenn.edu. J. Daniel Ragland, Ruben C. Gur, David C. Glahn, David M. Censits, Mark G. Lazarev, and Raquel E. Gur, Department of Psychiatry, University of Pennsylvania Health Systems; Robin J. Smith and Abass Alavi, Department of Radiology, University of Pennsylvania Health Systems. HHS Public Access Author manuscriptNeuropsychology. Author manuscript; available in PMC 2015 May 21. Published in final edited form as:Neuropsychology. 1998 July ; 12(3): 399-413. Author Manuscript Author ManuscriptAuthor Manuscript Author ManuscriptMore recently, researchers have begun to acknowledge the reciprocal interconnectivity of the prefrontal cortex with the hippocampus (Goldman-Rakic, Selem...

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