For rTMS, a wire coil is held on the patient's scalp. A brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the brain. The subject hears a click and may feel a pulling sensation on the skin under the coil. There may be a twitch in the muscles of the face, arm or leg. The subject may be asked to tense certain muscles slightly or perform other simple actions. The effect of TMS on the muscles is detected with small metal disk electrodes taped to the skin of the arms or legs. This study uses two kinds of rTMS. In one (Hz rTMS), magnetic pulses are given once per second for a period of 20 minutes; in the other (TBS), a series of pulses are given in bursts, each lasting 2 seconds, for a period of 3 minutes.