1. D. C. Adamson, B. Wildemann, M. Sasaki, V. I. Christov, T. M. Dawson, V. L. Dawson, Departments of Neurology, Neuroscience, and Physiology, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Pathology 2-210, Baltimore, MD 21287, USA.
2. J. D. Glass, Departments of Neurology and Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
3. J. C. McArthur, Department of Neurology, Johns Hopkins University School of Medicine, and Department of Epidemiology, Johns Hopkins University School of Hygiene and Public Health, Baltimore, MD 21287, USA.