1. a Department of Neurosurgery, Osaka University Medical School, Suita-shi, Osaka 565-0871, Japan;, Email: mhirata@nsurg.med.osaka-u.ac.jp
2. b Department of Neurosurgery, Osaka University Medical School, Suita-shi, Osaka 565-0871, Japan
3. c Department of Neurosurgery, Osaka University Medical School, Suita-shi, Osaka 565-0871, Japan
4. d Department of Neurosurgery, Osaka University Medical School, Suita-shi, Osaka 565-0871, Japan
5. e Department of Neurosurgery, Osaka University Medical School, Suita-shi, Osaka 565-0871, Japan
6. f University of Tokyo Interfaculty Initiative in Information Studies, Graduate School of Interdisciplinary Information Studies, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
7. g Graduate School of Information Science and Technology, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
8. h Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashihiroshima, Hiroshima 739-8530, Japan
9. i Group of Electrical Engineering, Communication Engineering, Electronic Engineering and Information Engineering, Tohoku University, Sendai, Miyagi 980-8578, Japan
10. j University of Tokyo Interfaculty Initiative in Information Studies, Graduate School of Interdisciplinary Information Studies, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
11. k ATR Computational Neuroscience Laboratories, Soraku-gun, Kyoto 619-0288, Japan
12. l Department of Neurosurgery, Osaka University Medical School, Suita-shi, Osaka 565-0871, Japan