[1] Centre de Recherches en Neurosciences Cognitives,
[2] Centre National de la Recherche Scientifique,undefined
[3] 31,undefined
[4] Chemin Joseph Aiguier,undefined
[5] F-13402 Marseille cedex 20,undefined
[6] France e-mail: thierry@lnf.cnrs-mrs.fr,undefined
[7] Fax: +33-4-91-77-49-69,undefined
[8] Neuroinformatics Laboratory,undefined
[9] National Institute of Bioscience and Human Technology,undefined
[10] Agency for Industrial Science and Technology,undefined
[11] Tsukuba,undefined
[12] Japan,undefined