[1] ULB Erasme, Neurophysiol Lab, B-1070 Brussels, Belgium
[2] ULB Erasme, Lab Expt Neurosurg, B-1070 Brussels, Belgium
[3] ULB Erasme, IRIBHN, B-1070 Brussels, Belgium
[4] CHU Grenoble, Hop A Michallon, UJF, EMI 0108 INSERM, F-38043 Grenoble 09, France
[5] INSERM, U422, F-59045 Lille, France