Paired Associative Stimulation in Stroke

Eligibility Details: Inclusion Criteria: 1. 18-80 years old; 2. first-ever ischemic stroke involving only one hemisphere; 3. Patient demonstrates at least 10 degrees of voluntary finger, thumb and wrist extension; ; 4. 6 - 24 months after ischemic stroke Exclusion Criteria: 1. Primary or secondary intracerebral hematoma, or subarachnoid hemorrhage, or subdural/epidural hematoma; 2. Bihemispheric ischemic strokes; 3. History of prior stroke or old infarct demonstrated on the CT or MRI or documented in medical records or current on anticoagulant; 4. Other concomitant neurological disorders, such as brain tumor, abscess or spinal cord disease affecting upper extremity motor function; 5. Documented history of dementia prior to index event; 6. Presence of any MRI/TMS risk factors such as (a) an electrically, magnetically or mechanically activated implant including cardiac pacemaker, intracerebral vascular clips or any other electrically sensitive support system; (b) non-fixed metal in any part of the body, including a previous metallic injury to eye [all jewelry will be removed during stimulation]; (c) pregnancy, since the effect of TMS on the fetus is unknown, females of child bearing age will have to undergo a pregnancy test to confirm eligibility; (d) history of seizure disorder or post-stroke seizures. This last exclusion criterion applies only to the modulation portion of the proposal; (e) median nerve is damaged