1. Institute of Scientific and Industrial Research (ISIR) Osaka University Mihogaoka 8‐1 Ibaraki Osaka 567‐0047 Japan
2. Endowed Research Department of Clinical Neuroengineering Global Center for Medical Engineering and Informatics Osaka University 2‐2 Yamadaoka Suita Osaka 565‐0871 Japan
3. Center for Information and Neural Networks National Institute of Information and Communications Technology (NICT) and Osaka University 1‐4 Yamadaoka Suita Osaka 565‐0871 Japan
4. Department of Neurosurgery Graduate School of Medical Sciences Kyushu University 3‐1‐1, Maidashi, Higashi‐ku Fukuoka 812‐8582 Japan
5. Japan Science and Technology Agency Precursory Research for Embryonic Science and Technology (PRESTO) 4‐1‐8 Honcho Kawaguchi Saitama 332‐0012 Japan
6. Department of Neurology Graduate School of Medicine Osaka University 2‐2 Yamadaoka Suita Osaka 565‐0871 Japan
7. Institute for Materials Chemistry and Engineering (IMCE) Kyushu University 744 Motooka, Nishi‐ku Fukuoka 819‐0395 Japan