Cerebral blood flow in schizophrenia: effects of memory processing on regional activation.

Regional cerebral blood flow (rCBF) was measured with the 133Xenon clearance technique and a high resolution (254 detectors) scanner during the performance of a verbal and a facial memory task in 18 patients with schizophrenia and 18 sociodemographically matched controls. Patients and controls had comparable resting rCBF, but differed in global and hemispheric rCBF changes induced by the memory 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 memory) 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 changes in other regions. Patients showed greatest impairment in specificity of verbal recognition performance, and this correlated with severity of hallucinations and delusions. This supports a model of left temporal lobe dysfunction in schizophrenia.