Réorganisation audiotactile suite à un entraînement multisensoriel ou à une privation auditive congénitale

Studies suggest that some sensory abilities may be increased in humans, either i) following training or ii) following early sensory deprivation. Studies suggest that such sensory alteration can be found in people who have undergone musical training. The interaction between what is heard and felt is especially important when an individual is playing a musical instrument. Musical training is well-known as a form of multisensory training that includes interactions between auditory, visual and tactile modalities. This can lead to anatomical and structural reorganizations in the cortical regions associated with these sensory systems. Several behavioral studies have revealed improved tactile perception skills in musicians. It is still unclear whether these improvements can be found for more complex processes, such as recognition of emotions. Similar alteration of tactile abilities may also be found in another population, namely early-deaf individuals. Imaging studies have shown that vibrotactile stimuli activate auditory regions following deafness, suggesting a significant tactile reorganization of their cortex. Yet, from a behavioral point of view, tactile perception in deaf seems similar to controls. Recently, it has been suggested that more complex tactile processes may reveal behavioral differences between deaf and normal-hearing individuals. Unfortunately, similarly to musicians, these processes have not been investigated to date. The main objective of this thesis is therefore to evaluate via non-musical and musical tasks i) tactile, auditory and multisensory perception of music among musicians and ii) tactile perception of music among deaf individuals.  For musicians, results of this thesis suggest enhanced auditory, tactile and audio-tactile frequency discrimination capabilities (Study 1). Also, results suggest an increase perception of emotions in music, which suggests improvements for complex auditory and tactile abilities (Study 2). These studies support the hypothesis that long-term musical training: i) leads to improved auditory and tactile perception, but especially that it extends to complex tactile processes, ii) has an impact at all hierarchical levels of sensory and cognitive processing For deaf individuals, results revealed a higher error rate during the tactile temporal order detection task (Study 3). This result suggests that spatial mapping of touch is impaired in deaf individuals. In addition, the study measuring tactile perception of emotion in music revealed that they are able to identify emotions via tactile modality solely. Also, improvements were found for the identification of happy emotion via tactile modality solely (Study 4). This increased ability to perceive happiness in a melody via the tactile modality illustrates that complex tactile skills can be improved following longstanding hearing deprivation. These two studies together suggest that complex non-musical and musical tactile abilities are altered in the deaf individual, which supports studies suggesting a cortical reorganization of auditory and tactile areas following long-term auditory deprivation.

Keyphrases: Perception auditive, Perception tactile, Musical training, Deafness, Perception of music, Auditory perception, Tactile perception, Multisensory integration, Brain plasticity