Cortical activation during foot movements: II effect of movement rate and side.

Cerebral control of foot movements has received limited study. Functional MRI compared slow with rapid foot movement, and right (dominant) with left foot movement. Brain activation during right, as compared with left, foot movement was larger, with higher amplitude task-related motor cortex signal change, and higher laterality index. Brain activation during fast, as compared with slow, foot movement was larger in cortical and cerebellar areas but smaller in deep gray areas. Some principles of cerebral control of hand movement extend to foot, but exceptions found include that dominant foot movement showed greater activation than did nondominant, and faster foot movements activated bilateral deep gray matter structures less than did slower. Results might have utility in trials of restorative therapies.