Motor-Evoked Potentials Following Imagery and Limb Disuse

This article investigated whether mental imagery training could reduce the detrimental effects produced by limb disuse. Subjects learned a task requiring fifth finger abduction. Motor-evoked potentials (MEPs) were obtained from the abductor digiti minimi muscle using transcranial magnetic stimulation. The arm was casted and the experimental group then practiced using imagery. After seven days, variable error scores increased. The immobilization treatment decreased MEP scores in both groups, with no difference between groups. It is concluded that limb immobilization produces a decrement in the area of motor cortex dedicated to this muscle as a result of disuse. Imagery failed to ameliorate the disuse-related changes.