1. Department of Biology, Stanford University, Stanford, CA 94305, USA.
2. Neurosciences Program, Stanford University, Stanford, CA 94305, USA.
3. Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
4. Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA.
5. Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA 94305, USA.
6. Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.