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.