Functional magnetic resonance imaging for the evaluation of the motor system: primary and secondary brain areas in different motor tasks.

Functional magnetic resonance imaging was used to characterize the primary and secondary motor system in subjects performing different motor tasks. Nine right-handed subjects performed simple motor tasks using hand, foot, knee, tongue, lips, eyes and the diaphragm-pelvis. All tasks revealed significant activation in primary and secondary motor areas. In the average across subjects, only the activity in the precentral gyrus was statistically distinctive for each motor task and followed the distribution of the motor homunculus. We consider these results as a possible basis of presurgical planning, extending the currently used procedures over a broader spectrum of motor tasks and brain structures leading to a more precise evaluation of functional areas for intracerebral interventions.