1. Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka 565‐0871, Japan
2. Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN, Hirosawa, Saitama 351‐0198, Japan
3. Formation of and information processing by neural networks, and control, PRESTO, Japan Science and Technology Agency (JST), 4‐1‐8 Hon‐cho, Kawaguchi, Saitama 351‐0198, Japan
4. Okazaki Institute for Integrative Bioscience, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444‐8787, Japan