1. Biosignal Research Center, Kobe University, Kobe 657‐8501, Japan
2. Department of Ophthalmology, Hyogo College of Medicine, Nishinomiya 663‐8501, Japan
3. Department of Medicine and Biochemistry, Division of Endocrinology, Diabetes and Metabolism, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
4. St. Vincent's Institute of Medical Research, Fitzroy, Victoria 3065, Australia