1. Department of Neurosurgery, Stanford University Medical Center, Stanford, CA 94305.
2. Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305.
3. Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford, CA 94304.
4. Department of Pathology, Stanford University Medical Center, Stanford, CA 94305.
5. Division of Neurosurgery, Santa Clara Valley Medical Center, San Jose, CA 95128.