1. Department of Neurology; Columbia University College of Physicians and Surgeons; New York, NY USA
2. Surgical Neurology Branch; National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda MD USA
3. Human Motor Control Section; National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda MD USA
4. Office of the Clinical Director; National Institute of Neurological Disorders and Stroke, National Institutes of Health; Bethesda MD USA