This study will examine whether transcranial magnetic stimulation (TMS) of the brain used in combination with carbidopa-levodopa is more effective in temporarily improving the speed of hand movement in stoke patients than TMS alone. In TMS, 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 effect of TMS on the muscles is detected with small metal disk electrodes taped to the skin of the arms or legs. Carbidopa-levodopa is a medication usually used to treat Parkinson's disease, but it may improve the effect of theta burst stimulation.