Theoretical Biology Laboratory, RIKEN, Wako, Japan.|Department of Anatomy and Neurobiology, Kindai University Faculty of Medicine, Osakasayama City, Osaka, Japan.|Department of Anatomy and Neurobiology, Kindai University Faculty of Medicine, Osakasayama City, Osaka, Japan.|Theoretical Biology Laboratory, RIKEN, Wako, Japan.|Department of Anatomy and Neurobiology, Kindai University Faculty of Medicine, Osakasayama City, Osaka, Japan.