H ORIGINAL ARTICLES Cerebral Blood Flow in Schizophrenia: Effects of Memory Processing on Regional Activation Raquel E. Gur, Jurg L. Jaggi, Derri L. Shtasel, J. Daniel Ragland, and Ruben C. Gur Regional cerebral blood flow ( rCBF) was measured with the mXenon clearance technique and a high resolution (254 detecwrs) scanner during the performance of a verbal and a facial memory task in 18 patients with schizophrenia and 18 sociodemographically matched controls. Patients and cm~trols had comparable resting rCBF, but differed in global and hemispheric rCBF changes induced by the mentor?/tasks. Patients had less global increase, which was relatively higher in the left hemisphere, and this was more pronounced for the verbal task. Although controls showed appropriate laterality changes (L > R for verbal and R > L for facial memm:y) in the midtemporal region, patients failed to show such a focal pattern. They did not show appropriate laterality change in the midtemporal region, but instead showed such chmtges in other regions. Patients showed greatest hnpainnent in specificity of verbal recogni- tion performance, and this correlated with severity of hallucinations and delusions. This supports a model of left temporal lobe dysfunction in schizophrenia. Key Words: Schizophrenia, memory, cerebral blood flow, neuroimaging Introduction The study of brain function in schizophrenia requires inte- gration of behavioral and physiologic data. This can be achieved through the application of neurobehavioral probes concurrent with physiologic measures (Gur et ai 1983, 1985; Weinberger et a11986, 1988; Buchsbaum et a11990). By applying conceptually guided probes, which yield reli- able performance data, hypotheses linking activation pat- terns with deficits can be effectivelytested (Gur et al 1992). Investigations measuring rCBF and metabolism during activation in schizophrenia have used the ~~3Xenon inhala- tion method (Gut et al 1983, 1985; Weinberger et al 1986, 1988), single photon computerized emission tomography (SPECT; Rubin et al 1991) and positron emission tomogra- phy (PET; Buchsbaum et al 1990; Voikow et al 1988). Most From the Department of Psychiatry. Neuropsychiatry Program University of Penn- sylvania, Phil,tdelphia. PA. Address Reprint Requests to Raquel E. Gur. MD. Department of Psychiatry. Neurop- sychiatry Program, 10th Floor Gates Bldg.. University tff Pennsylvania. Philadel- phia. PA 10104. Received December 7, 1992; revised September 20. 1993. © 1994 Society of Biological Psychiatry have centered on two brain dimensions, anterior-posterior and laterality, and have reported failure to activate the dor- solateral prefrontal cortex during performance of the Wis- consin Card Sorting Test (Weinberger et al 1986), reduced frontal and parietal metabolism when engaged in the contin- uous performance task (Buchsbaum et al 1990) and an ab- normal pattern of laterality during performance of verbal and spatial tasks (Gur et al 1983). These studies suggest distinct topography of brain activation during task perfor- mance in schizophrenia, which corroborate neuropsy- chological impairment in the disorder (Bilder et al 1991; Saykin et a11991). The potential role of the temporal lobe in the pathophysi- ology of schizophrenia has received support from examina- tion of clinical features (FIor-Henry 1969), neuroanatolnic magnetic resonance imaging (MRI) studies (Suddath et al 1989; Shenton et al 1992; DeLisi et al 1992), and neuro- pathologic research (Bogerts et al 1991; Arnold et al 1992). Temporal lobe dysfunction has been linked to memory dis- turbances (Milner 1967; Squire and Zola-Morgan 1991). We examined the profile of neuropsychological functioning 0~Xlf-3223/O4/$O7,~K)