1 Computation and Neural Systems Program, California institute of Technology,
Pasadena, CA 91125, USA
2 JST.ERATO Shimojo "Implicit Brain Functions" Project, Japan
3 Summer Undergraduate Research Fellowship Program, California institute of Technology,
Pasadena, CA 91125, USA
1 Computation and Neural Systems Program, California institute of Technology,
Pasadena, CA 91125, USA
2 NTT Communication Science laboratories, Atsugi, Kanagawa, 243 Japan