1. Graduate School of Science, Kobe University, Kobe 657-8501, Japan
2. Institute for Chemical Research, Kyoto University, Kyoto 611-0011, Japan
3. Department of Systems Biology, Harvard Medical School, Boston, MA 02215, U.S.A.
4. Graduate School of Science and Technology, Kobe University, Kobe 657-8501, Japan
5. Biosignal Research Center, Kobe University, Kobe 657-8501, Japan