Hypofrontality in unmedicated schizophrenia patients studied with PET during performance of a serial verbal learning task

Previous research indicates that verbal learning and memory deficits are am ong the most severe cognitive deficits observed in schizophrenia. However, the concomitant patterns of regional brain function associated with these d eficits in schizophrenia are not well understood. The present study examine d verbal-memory performance and simultaneous relative glucose metabolic rat es (rGMR) with FDG PET in 20 unmedicated schizophrenia patients who met str ingent memory-performance criteria and 32 age- and sex-matched normal volun teers. On a modified version of the California Verbal Learning Test, patien ts recalled fewer correct words using a semantic-clustering strategy and ex hibited more intrusions compared with normal subjects. However, patients ha d higher serial-ordering strategy scores, indicating their use of a less ef ficient organizational strategy. Among patients, greater use of the serial- ordering strategy was associated with decreased rGMR in frontal cortex and increased rGMR in temporal cortex. Patients had lower rGMR primarily in fro ntal and temporal cortex, but not parietal and occipital lobe regions. Pati ents also exhibited hypofrontality (lower ratio of frontal to occipital rGM R) compared with normal subjects. Among the patients, more severe hypofront ality was associated with increased perseveration errors. (C) 2000 Elsevier Science B.V. All rights reserved,