1. Department of Neurosurgery, Sapporo Medical University, School of Medicine, Sapporo, Hokkaido, Japan
2. Department of Neurology, Sapporo Medical University, School of Medicine, Sapporo, Hokkaido, Japan
3. Department of Systems Neuroscience, Sapporo Medical University, School of Medicine, Sapporo, Hokkaido, Japan
4. Department of Pediatrics, Hokkaido University Graduate, School of Medicine, Sapporo, Hokkaido, Japan