Abstract
Our ability to merge information coming from several senses is crucial to produce and regulate our body movements. The main objective of this thesis is to study the effects of multisensory integration factors on our sensorimotor rhythmic behaviours. The multisensory integration effects on these behaviours are not well understood, being seldom studied. However, those behaviours characterize most of our daily activities such as walking, writing or doing sports. So far, multisensory processes have essentially been studied with regard to our discrimination and detection skills, highlighting the necessity of a temporal synchrony between senses for their integration. The consequences of this temporal coherence and the associated mechanisms have never been tested on sensorimotor rhythmic behaviours. Thus, we will extend their effects to these behaviours. Besides, literature shows that the movements’ features modify the processing of sensory information and can influence multisensory integration. We will test the effects of the stability of the sensorimotor system, i.e. intrinsic stability of gait, on the multisensory integration.The two main contributions of the thesis are the following ones: (1) Rhythmic behaviours obey the same principles as temporal discrimination and detection behaviours. Our results generalize the effects of temporal coherence and show for the first time a multisensory benefit on gait. (2) We suggest a novel sensorimotor compensatory assumption, highlighting the adaptive use of multisensory information by the sensorimotor system, which compensates the decrease of the intrinsic stability of the gait with a larger and/or better use of external audio-tactile information.