Adaptation of the Motor System to Experimental Pain

Experimental pain will be induced by capsaicin 1% on intact, non-irritated and dry shoulder's skin. For the purposes of this study, we will remove this patch before the recommended application time in order to generate a pain. The participant will be seated on a chair facing a table so that his or her dominant forearm rests on the table. Markers will be placed at the table and chair legs as well as on the table, corresponding to the two support points of the elbow and the index finger, in order to standardize the starting position. The target of the pointing movement will be placed at 80% of this maximum distance. The investigator will tell the participant to stand by, and then, within 4 to 10 seconds, an audible signal will indicate to the subject that he/she should perform the pointing movement. The procedure will repeat after a 4-10 second pause. For each session, 30 pointing movements reaching the target will be performed.