注意力對疼痛習慣化的調節機轉

Abstract

In daily life, different top-down cognitive modulations are intermingled to shape human experiences of pain, but the neural mechanisms underlying the complex interactions of these factors remain largely unknown. Among the various cognitive factors, habituation (i.e., decreased responses to repetitive painful stimuli) and attention (e.g. directing attention away from pain reduces pain sensation) are two important processes that can provide immediate pain relief, and the aberrance of these processes has been suggested to play important roles in chronic pain. In the present functional MRI study, we asked whether distraction affects the influence of habituation on pain processing and investigated the underlying cerebral mechanisms. Participants underwent repetitive painful or non-painful stimuli to the leg skin when their attention towards stimuli was distracted to different degrees in Stroop tasks. Behavioral results showed that distraction accelerated habituation of pain but not non-pain. At the neural level, we found that the neural signal in the subgenual anterior cingulate cortex reflected the effect of distraction on pain. Although activation in the anterior insula tracked the degree of pain habituation, distraction has no effect on the relationship between insular activity and pain habituation. In contrast, distraction significantly altered the correlation between the extent of pain habituation and the activity in the subgenual anterior cingulate cortex. These findings suggest that the neural mechanisms underlying pain modulation by distraction also contribute to the effect of distraction on pain habituation, which provides new insights into the understanding of chronic pain mechanisms in the future.