1. Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea.
2. Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA.
3. Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
4. Graduate School of Medicine, Korea University, Seoul 136-705, Korea.
5. Department of Surgery, Ajou University School of Medicine, Korea.
6. Brain Disease Research Center, Ajou University School of Medicine, Korea.
7. Department of Biological Sciences, College of Natural Science, Ajou University, Suwon 443-749, Korea.