1. Department of Neurosurgery, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan.
2. Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut.
3. Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut.
4. Department of Molecular Medicine, Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan.