RIKEN Brain Science Institute, Wako-shi, Saitama, Japan. shimazaki@brain.riken.jp|RIKEN Brain Science Institute, Wako-shi, Saitama, Japan. shimazaki@brain.riken.jp|RIKEN Brain Science Institute, Wako-shi, Saitama, Japan. shimazaki@brain.riken.jp|RIKEN Brain Science Institute, Wako-shi, Saitama, Japan. shimazaki@brain.riken.jp