1. Sanford-Burnham Medical Research Institute, Del E. Webb Center for Neuroscience, Aging, and Stem Cell Research, La Jolla, California.
2. Department of Pediatrics and Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California.
3. Department of Neurosciences, University of California, San Diego, La Jolla, California.
4. Division of Biological Sciences, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California.