FUNCTIONAL MAGNETIC-RESONANCE-IMAGING OF MOTOR CORTEX - HEMISPHERIC-ASYMMETRY AND HANDEDNESS

A hemispheric asymmetry in the functional activation of the human moto r cortex during contralateral (C) and ipsilateral (I) finger movements , especially in right-handed subjects, was documented with nuclear mag netic resonance imaging at high field strength (4 tesla). Whereas the right motor cortex was activated mostly during contralateral finger mo vements in both right-handed (C/I mean area of activation = 36.8) and left-handed (C/I = 29.9) subjects, the left motor cortex was activated substantially during ipsilateral movements in left-handed subjects (C /I = 5.4) and even more so in right-handed subjects (C/I = 1.3).