1. Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea.
2. Institute of Tissue Engineering (ITREN), Dankook University, Cheonan, Korea.
3. Department of Anatomy, Dankook University College of Medicine, Cheonan, Korea.
4. Department of Orthopedics, Brown University, Providence, RI, USA.
5. BK 21 Project for Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea.