Cognitive distraction from pain: An fMRI study on the role of age and executive functions

Completing a cognitive task has been shown to be a powerful strategy to reduce concurrent pain.
This reduction in pain is assumed to result from a competition between the painful stimulus and the distractive task for attentional and executive resources mediated by the prefrontal cortex (PFC), a region that is particularly affected by age-related grey matter atrophy. In the present study, we investigated the role of age-related changes in gray matter volume and executive functions in modulating the efficacy of distraction from pain.

In a first session, young and older adults completed a battery of neuropsychological tests. In a second session, we acquired functional brain images while participants completed a working memory task with two levels of cognitive load (low vs. high load) and concurrently received individually adjusted heat stimuli (innocuous vs. painful) to their lower arm.

While we found no age-related differences in the distraction effect size on the behavioural level, young adults showed a larger neural distraction effect in several regions involved in pain processing, including the insula, caudate and midcingulate cortex. Interestingly, older adults with better executive functions, particularly, better inhibitory control abilities, showed a larger neural distraction effect in the insula, thalamus and primary somatosensory cortex, and more activation in frontal clusters during the high load task.

Taken together, these findings suggest that age alters the neural mechanisms underlying cognitive distraction from pain, and that the magnitude of these changes may be dependent on the preservation of executive functions.