FMRI APPLICATIONS IN SCHIZOPHRENIA RESEARCH

fMRI has unique potential in the study of psychiatric patients, partic ularly in characterizing individual variations and changes over time. We have performed four studies of patients with schizophrenia, using t hree different fMRI acquisition protocols: (1) 3-D echo-shifted FLASH, a multishot volumetric approach; (2) 3-D PRESTO, a hybid of multishot and echo-planar imaging (EPI) methods that also acquires true volumet ric data; and (3) a whole-brain isotropic, multislice EPI technique. P atients were studied during sensorimotor activation and during a novel ''N back'' working memory paradigm. In general, patients show normal sensorimotor activation responses, although motor cortical activation tends to be less completely lateralized. Prefrontal activation during working memory tends to be reduced in patients with schizophrenia even when performance is normal. A major potential confound in studying th is patient population with fMRI is the effect of motion. We propose se veral methodological standards to address this problem, including comp arisons of motion corrections parameters, voxel variances, and the use of an ''internal activation standard.'' (C) 1996 Academic Press, Inc.