The impact of thermal and auditory unpleasant stimulus on explicit motor imagery in healthy individuals: An experimental study

Motor imagery is the ability to mentally simulate a motor task without actually performing it. Furthermore, pain is an unpleasant sensory experience that involves different dimensions - sensory-discriminative, motivational-affective, and cognitive-evaluative - that are known to interfere with motor imagery. However, it remains unclear which specific pain dimension most significantly impairs motor imagery vividness. This study aims to compare the effects of unpleasant auditory (primarily affective and cognitive) and thermal (primarily sensory) stimuli, which can be assimilated to pain, on discrete and continuous explicit motor imagery sessions. Eighteen healthy participants were exposed to these unpleasant stimuli in addition to a control condition. Participants rated the vividness of their explicit motor imagery after performing full back-and-forth flexion and extension of their wrists in discrete and continuous sessions. Results showed that during discrete explicit motor imagery, only the aversive auditory stimulus significantly reduced motor imagery vividness, whereas thermal pain had no effect. In contrast, motor imagery vividness was preserved during the continuous session. These findings suggest that explicit motor imagery may be more affected by the affective dimension of pain induced by aversive auditory stimuli. The preservation of motor imagery vividness in the continuous session provides insight into the optimization of rehabilitation programs.