1. From the Department of Neurology (J.C.G.), University of Texas-Houston Medical School; Extramural Research Program (T.P.J.) and NINDS Office of the Director (W.J.K.), National Institutes of Health/National Institute of Neurological Diseases and Stroke, Neuroscience Center, Bethesda, Md; and Harvard Medical School (M.A.M.), Massachusetts General Hospital, Neurology/Neurosurgery, Charlestown.