1. Neurotechnology Center, Department of Biological Sciences, Columbia University, 550 West 120 Street, Box 4822, New York, NY 10027, USA
2. Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
3. The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
4. RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama351-0106, Japan