Participants will undergo TMS and the electrical activity in muscles activated by the stimulation will be recorded. For TMS, an insulated wire coil is placed on the patient's scalp, and a brief electrical current is passed through the coil. This creates a magnetic pulse that travels through the scalp and skull and causes small electrical currents in the outer part of the brain. If the coil is placed over a nerve that controls muscles, there may be a twitch in the muscles, sometimes large enough to move the face. In other cases, there may be a feeling of movement or tingling sensation in the face. Stimulation over the muscles on the side of the head may cause some discomfort there or twitching of the jaw. During the stimulation, subjects may be asked to tense certain muscles slightly or perform other simple actions.