The Impact of Emotion Regulation on the Emotional Modulation of Cortical Potentials in Response to Nociceptive Input

Abstract: Emotions impact pain; appetitive (pleasant) emotions reduce pain, and aversive (unpleasant) emotions increase pain. Emotion regulation (ER) strategies can alter emotional experience, and we have shown that ER can alter emotional modulation of pain, but not emotional modulation of spinal nociception (as assessed by nociceptive flexion reflex, NFR). The current study examined whether ER influences the emotional modulation of cortical event-related potentials (ERPs) in response to nociceptive input. To investigate, 68 pain-free individuals viewed pleasant (erotic), neutral, and unpleasant (mutilation) pictures during which painful electric stimulations were delivered. Participants viewed one block of pictures without engaging in ER and were then randomly assigned to ER (suppress or enhance) employed during a second block of pictures. Picture-evoked valence and arousal ratings, skin conductance response, and corrugator electromyogram (EMG) suggested that ER successfully regulated emotional experience. Instructions to suppress led to a significant reduction of emotional modulation of self-reported pain (i.e., reducing pleasure-induced pain inhibition and displeasure-induced pain facilitation), but neither NFRs nor ERPs were affected. Paradoxically, enhance instructions had no effect on pain or NFR, but were associated with a general suppression of the P260 ERP, indicating non-specific emotional arousal up-regulation. Findings indicate ER can independently impact emotional modulation at perceptual and supraspinal levels, but does not impact spinal nociception. Given that emotional suppression led to decreases in displeasure-evoked pain facilitation without reducing displeasure-evoked facilitation of spinal or supraspinal responses to nociception, future research should determine whether this divergence is associated with positive or negative long-term consequences.