Functional magnetic resonance imaging at 1.5 T: activation pattern in schizophrenic patients receiving neuroleptic medication.

Activation of the cerebral cortex during motor task performance can be visualised with functional MRI. A modified FLASH sequence (TR/TE/alpha 100/60/40 degrees, first order flow rephased, fat suppression, reduced bandwidth 28 Hz/pixel, 120 repetitions, three cycles of rest and finger movement for each hand) on a standard 1.5 T clinical imager was used to investigate 10 schizophrenic patients receiving clozapine and 10 healthy volunteers. All subjects were right-handed. Color-coded statistical parametric maps (SPM) based on the Student's t-test were calculated. A grid overlay was used for global and regional quantification. Activation strength was defined as the mean t-value of the respective region. All patients and volunteers showed a significant activation in the contralateral and ipsilateral sensorimotor cortex during motor task performance. The schizophrenic patients showed a significantly reduced global activation strength compared with healthy volunteers (p < .005). Selective evaluation of left-hand compared to right-hand movement demonstrated an increase in global activation strength in volunteers in contrast to a decrease in patients. Furthermore a reduced coactivation in the dominant left hemisphere was found in patients compared to volunteers during movement of the ipsilateral (left) hand. We conclude that alterations of the right and left hemispheric balance can be detected in schizophrenic patients using functional MRI at 1.5 T. These changes may indicate a disturbed interhemispheric interaction in schizophrenia. The reduction in cortical activation may result from several causes, however, taken together with previous studies and the underlying physiological effects, the most likely explanation is a combined effect of the disease and the neuroleptic medication.