1. Department of Precision Engineering, School of Engineering, The University of Tokyo: 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
2. Research into Artifacts, Center for Engineering (RACE), School of Engineering, The University of Tokyo, Japan
3. Department of Pain and Palliative Medicine, The University of Tokyo Hospital, Japan
4. Division on Neuroscience, Department of Physiology, Asahikawa Medical University, Japan