Participants will be asked to show the sensory trick and may be asked to be videotaped. During the TMS procedure, they will be seated in a comfortable chair, with hands placed on a pillow on the lap. Small electrodes-soft strips that stick to the skin-will be placed on the skin to record the electrical activity of some muscles in the neck that are activated by the stimulation from TMS. In TMS, there will be a wire coil held over the scalp. A brief electrical current will be passed through the coil, creating a magnetic pulse that stimulates the brain. Patients will hear a click and may feel a pulling sensation on the skin under the coil. There may be muscle twitches of the face, arm, or leg. In addition, patients may be asked to tense certain muscles slightly or perform other simple actions so that the coil can be positioned appropriately. Patients will sometimes be asked to bite down and tap their teeth slightly for about 1-1/2 minutes at a time. They will be asked to show the sensory trick. The stimulation is usually not painful, although sometimes strong contractions of the scalp muscles can cause discomfort or a headache. Patients can ask to have the procedure discontinued at any time. The testing session takes about 2 hours, done on an outpatient basis.