Neurocognitive evidence for mental imagery-driven hypoalgesic and hyperalgesic pain regulation
Mental imagery has the potential to influence perception by directly altering sensory, cognitive, and affective brain activity associated with imagined content.
Mental imagery has the potential to influence perception by directly altering sensory, cognitive, and affective brain activity associated with imagined content. While it is well established that mental imagery can both exacerbate and alleviate acute and chronic pain, it is currently unknown how imagery mechanisms regulate pain perception. For example, studies to date have been unable to determine whether imagery effects depend upon a general redirection of attention away from pain or focused attentional mechanisms. To address these is- sues, we recorded subjective, behavioral and ERP responses using 64-channel EEG while healthy human partic- ipants applied a mental imagery strategy to decrease or increase pain sensations. When imagining a glove covering the forearm, participants reported decreased perceived intensity and unpleasantness, classified fewer high-intensity stimuli as painful, and showed a more conservative response bias. In contrast, when imagining a lesion on the forearm, participants reported increased pain intensity and unpleasantness, classified more low- intensity stimuli as painful, and displayed a more liberal response bias. Using a mass-univariate approach, we fur- ther showed differential modulation of the N2 potentials across conditions, with inhibition and facilitation re- spectively increasing and decreasing N2 amplitudes between 122 and 180 ms. Within this time window, source localization associated inhibiting vs. facilitating pain with neural activity in cortical regions involved in cognitive inhibitory control and in the retrieval of semantic information (i.e., right inferior frontal and temporal regions). In contrast, the main sources of neural activity associated with facilitating vs. inhibiting pain were iden- tified in cortical regions typically implicated in salience processing and emotion regulation (i.e., left insular, inferior-middle frontal, supplementary motor and precentral regions). Overall, these findings suggest that the content of a mental image directly alters pain-related decision and evaluative processing to flexibly produce hypoalgesic and hyperalgesic outcomes.
© 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license