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/alph a 100/60/40 degrees, first order flow rephased, fat suppression, reduc ed bandwidth 28 Hz/pixel, 120 repetitions, three cycles of rest and fi nger movement for each hand) on a standard 1.5 T clinical imager was u sed to investigate 10 schizophrenic patients receiving clozapine and 1 0 healthy volunteers. All subjects were right-handed. Color-coded stat istical parametric maps (SPM) based on the Student's t-test were calcu lated. 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 i n the contralateral and ipsilateral sensorimotor cortex during motor t ask performance. The schizophrenic patients showed a significantly red uced global activation strength compared with healthy volunteers (p < .005). Selective evaluation of left-hand compared to right-hand moveme nt demonstrated an increase in global activation strength in volunteer s in contrast to a decrease in patients, Furthermore a reduced coactiv ation in the dominant left hemisphere was found in patients compared t o volunteers during movement of the ipsilateral (left) hand. We conclu de that alterations of the right and left hemispheric balance can be d etected in schizophrenic patients using functional MRI at 1.5 T. These changes may indicate a disturbed interhemispheric interaction in schi zophrenia. The reduction in cortical activation may result from severa l causes, however, taken together with previous studies and the underl ying physiological effects, the most likely explanation is a combined effect of the disease and the neuroleptic medication.