1Department of Physiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
2Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
3Department of Biological Information Processing, Graduate School of Electronic Science and Technology, Shizuoka University, Hamamatsu, Shizuoka 432-8011, Japan
4Department of Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan