1. Department of Stem Cell and Regenerative Biology, and Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA.
2. MGH-HMS Center for Nervous System Repair, Departments of Neurology and Neurosurgery, and Program in Neuroscience, Harvard Medical School; Nayef Al-Rodhan Laboratories, Massachusetts General Hospital, Boston, MA 02114, USA.
3. Nencki Institute of Experimental Biology, Department of Molecular and Cellular Neurobiology, Warsaw, 02-093, Poland.
4. Departments of Neurology and Pathology, and Program in Neuroscience, Harvard Medical School; Center for Life Sciences, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
5. Beth Israel Deaconess Medical Center, Division of Endocrinology, Diabetes, and Metabolism, and Harvard Medical School, Boston, MA 02215, USA.
6. Harvard Medical School, Boston, MA 02215, USA.