1. Neural Network Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan.
2. Anatomy and Cell Biology, Nagoya University Graduate School of Medicine, Aichi 466-8550, Japan.
3. Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan.
4. Department of Biology, Ochanomizu University, Tokyo 112-8610, Japan.
5. Graduate School of Humanities and Sciences, Ochanomizu University, Tokyo 112-8610, Japan.
6. School of Advanced Science and Engineering, Waseda University, Tokyo 169-0072, Japan.
7. Neural Development Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan.