Study of Cerebral Activation by fNIRS During Gait With Different Rhythmic Auditory Stimulations in Healthy Subjects

The purpose of this study is to investigate the cerebral activation in healthy subjects in 4 conditions of gait : * Gait at preferred cadence without auditory stimulation (Gait1) * Gait with low tempo rhythmic auditory stimulation by music (RAS-Slow). The beat rate of the music was 68.5 per minute for all participants. * Gait with fast tempo synchronous rhythmic auditory stimulation by music (RAS-Fast). The beat rate of the music was set to 10% above each patient's preferred gait cadence . The preferred cadence was considered as the mean of the 6 trials during Gait 1. * Gait without auditory stimulation (Gait2) The investigators goal is to compare cerebral activation and gait parameters during the 4 different tasks using fNIRS.