1. Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences; Kagoshima University; Kagoshima 890-8544 Japan
2. Department of Morphological Brain Science, Graduate School of Medicine; Kyoto University; Kyoto 606-8501 Japan
3. Division of Brain Circuits; National Institute for Basic Biology; Okazaki Aichi 444-8585 Japan
4. Department of Dental Anesthesiology, Graduate School of Medical and Dental Sciences; Kagoshima University; Kagoshima 890-8544 Japan