Figure 2.

Corticospinal excitability during movement preparation. TMS was delivered at three timings (x-axis) before subjects grasped and lifted the objects. The MEP ratio (y-axis) was obtained by dividing MEPs recorded when preparing lifts preceded by a heavy object by MEPs recorded when preparing a lift preceded by a light object. A, MEP ratio when preparing to lift objects of unknown weight. B, MEP ratio when preparing to lift objects of visible weight (light, white; heavy, gray). C, MEP ratio between MEPs recorded during preparation of lift of a heavy object and a light object but both preceded by an object of the same weight (light, white; heavy, gray). *p < 0.05.