 Threshold determination and stimulation location will be performed using each subjects most affected hand, or the non-dominant hand if both hands are affected. The location of lowest threshold for stimulation of the FDI will be determined by gradual movement of the stimulation coil over the surface of the contralateral scalp, in the region of the standard C3 or C4 electrode position determined by international 10-20 EEG electrode placement convention. The handle of the stimulation coil will be pointed backward and 45 degrees from the sagittal plane so as to be approximately perpendicular to the rolandic fissure. The location of minimum threshold will be marked with a washable non-permanent marker on the subjects scalp in order to ensure consistency of stimulation. 