1. Paul F. Glenn Laboratories for the Biology of Aging and Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
2. Anatomy Department, Institute of Biomedical Sciences, University of São Paulo, 2415 Lineu Prestes Avenue, São Paulo, São Paulo 05508-000, Brazil.
3. Neurology Service, VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304, USA.