1. Department of Neurology, McGaw Medical Center of Northwestern University, Chicago, Illinois, USA.
2. Stroke Branch, National Institute of Neurological Disorders and Stroke Intramural Research Program, Bethesda, Maryland, USA.
3. Department of Neurology, Columbia University Irving Medical Center, New York, New York, USA.
4. Laboratory of Behavioral Neuroscience, National Institute on Aging, Baltimore, Maryland, USA.
5. Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA.
6. Division of Epidemiology and Community Health, University of Minnesota School of Public Health, Minneapolis, Minnesota, USA.