1. Okinawa Institute of Science and Technology, Computational Neuroscience Unit Onna-son, Okinawa, Japan
2. Department of Neuroscience, Neuroscience Institute, Cavalieri Ottolenghi, University of Turin, Turin, Italy
3. INRIA, F-69603 Univ Lyon, LIRIS, UMR5205 CNRS, Villeurbanne, France
4. Okinawa Institute of Science and Technology, Computational Neuroscience Unit, Onna-son, Okinawa, Japan