Background and aims: Behavioural studies repeatedly evidenced that nociceptive stimuli can affect the perception of external visual information near the simulated body part. We investigated neurophysiological mechanisms of such multisensory interaction between nociception and vision. We hypothesised that nociceptive stimuli can influence cortical visual pathways, and more specifically the interhemispheric asymmetry of brain responses to lateralised visual stimuli. Methods: 28 healthy participants made temporal order judgements (TOJs) on pairs of light flashes presented one in either side of space with different onset asynchronies. They were shortly preceded by a nociceptive stimulus randomly delivered to the left or right hand. We compared between the two hemispheres the amplitude of the event-related potentials (ERPs) to simultaneous visual stimuli. Results: TOJs were significantly biased towards perceiving the light on the side of the nociceptive stimulus as having flashed earlier than the light on the opposite side. Mean amplitude of the visual ERPs was significantly larger over the hemisphere contralateral to the side of the nociceptive stimulus, relative to the response over the ipsilateral hemisphere, mostly over parietal-occipital area at 100-160 msec after bilateral lights’ onset. Conclusions: This data shows that nociceptive stimuli can affect cortical processing of visual stimuli at a relatively early latency in extra-striate areas. The effect is thought to index cortical mechanisms by which one’s attention is drawn towards the portion of visual space surrounding the body part on which nociceptive stimuli are applied.
Kuzminova, Avgustina
[UCL]
