Surface electromyographic responses were recorded from 9 human abductor policies brevis muscles in response to transcranial magnetic stimulation of the brain with 100% of maximal stimulator output, the subject being at rest, contracting with 10% of the maximal muscle activity of APB, and thinking about thumb abduction but with no detectable EMG activity. Stimulation was delivered at the scalp location where 75 or 85% output evoked the largest muscle response. Threshold was determined as the smallest stimulator output to produce at least 4 motor responses (50 μV and over) out of 8 stimuli. The thresholds ranged from 65 to 85% output, and averaged 73%. Thus, relative stimulus intensity of 100% output to threshold ranged from 118 to 167% threshold, and averaged 137 %threshold. Following magnetic stimulation with 100% output, median amplitude of evoked responses during thinking about the movement was approximately twice larger than at rest (p=0.0077), and a half of that during voluntary contraction (p=0.0077). To standardize the degree of facilitation, the amplitude ratios of response during thinking, and voluntary contraction to that at rest were calculated. The thinking/rest ratios ranged from 1.1 to 6.3, and averaged 2.2. The contraction/rest ratios ranged from 2.3 to 18.6, and averaged 7.4. These findings show that thinking about the movement has a facilitatory effect on the evoked potentials to magnetic stimulation of the brain, and that the degree of facilitation in thinking is smaller than in voluntary contraction.