1. Department of Robotics College of Science and Engineering Ritsumeikan University Nojihigashi, Kusatsu Shiga Japan
2. Systems Neuroscience Section Department of Rehabilitation for Brain Functions Research Institute of National Rehabilitation Center for Persons with Disabilities Tokorozawa Saitama Japan
3. Department of Physiology Dokkyo Medical University School of Medicine Mibu Tochigi Japan
4. Center for Neuroscience and Biomedical Engineering The University of Electro‐Communications Chofu Tokyo Japan