1 Division of System Neurophysiology, National Institute for Physiological Sciences, Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan. Electronic address: nambu@nips.ac.jp.
2 Chubu University Academy of Emerging Sciences, Kasugai, Aichi 487-8501, Japan.
3 The Graduate School of Core Ethics and Frontier Sciences, Ritsumeikan University, Kyoto, 603-8577, Japan.