1. Department of Neurosurgery, Kangwon National University School of Medicine, Chuncheon, Korea
2. Divisions of Applied Animal Science and Animal Resource Science, Department of Animal Life Science, Kangwon National University, Chuncheon, Korea
3. Department of Thoracic and Cardiovascular Surgery, Kangwon National University School of Medicine, Chuncheon, Korea
4. Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea