| Pain is a complex experience comprising both a sensory and an affective dimension. As a consequence of this affective dimension, emotions have been shown to easily influence our perception of pain. Although many therapeutic interventions, such as music therapy, seem to depend on this phenomenon to reduce pain, the implication of emotions in their analgesic effect has never been empirically assessed. Moreocer, the cerebral mechanisms explaining the effects of emotions on pain remain relatively unknown. The objectives of this thesis are thus to highlight the involvement of emotions in music-induced analgesia and to examine the cerebral and cerebra-spinal mechanisms involved in the emotional modulation of pain.;In the fourth experimental article, we contrasted the effects of attention and emotion on spinal nociception (RIII reflex) in 33 participants. While emotions influenced the RIII reflex and pain ratings in parallel, distraction increased the reflex, but reduced pain perception, suggesting that different neurophysiological mechanisms might be involved in the emotional and attentional modulation of pain. Finally, in the fifth and last article of the thesis, we explored the cerebral mechanisms involved in the emotional modulation of pain using the same experimental paradigm in a functional magnetic resonance imaging (fMRI) study in 13 participants. The activation of the paracentral lobule, the right insula and the parahippocampal gyrus in response to pain was increased by unpleasant compared to pleasant pictures. The modulation of the paracentral lobule appeared to be the result of descending modulatory mechanisms, whereas the modulation of the right insula was linked to cortico-eortical mechanisms. Finally, the modulation of the parahippocampal gyrus seemed to be caused by a convergence of the effects of pain and emotions.;Altogether, these results bring a strong theoretical support for the use of emotional induction techniques, such as music therapy, as therapeutic agents for pain management in clinical settings.;Key words: Pain, emotion, music, brain, fMRI, spinal cord, RIII reflex.;In order to distinguish the role of emotions and attention in music-induced analgesia, the first experimental study of the thesis compared the effects of pleasant and unpleasant musical excerpts on pain perception in 18 participants. Although the unpleasant excerpts were also distracting, only the pleasant excerpts managed to reduce pain, supporting the involvement of emotional processes in music-induced analgesia. In the second experimental article, we tested the capacity of music to induce emotions by assessing the effects of the same musical excerpts on the startle reflex in 16 participants. The reflex, which is a sign of activation of the defensive emotional system, was enhanced by unpleasant music and diminished by pleasant music, confirming the capacity of music to induce emotions. Finally, in the third experimental article, we explored the neurophysiological mechanisms involved in the effects of music on pain by measuring the influence of musically-induced emotions on a spinal nociceptive reflex (RIII reflex) in 26 participants. The results showed that the RIII was modulated by the emotions induced by music, suggesting the involvement of descending modulatory mechanisms in music-induced analgesia. |
