The effect of emotion regulation on the emotional modulation of pain and nociceptive flexion reflex.

Positive emotions inhibit pain, whereas negative emotions facilitate pain. Thus, many psychosocial interventions capitalize on this emotion-pain relationship to improve patients' abilities to regulate emotion (ie, reduce negative emotion, increase positive emotion), influence nociception, and manage pain. This study extended the existing literature to examine whether emotion regulation procedures could influence emotional modulation of the nociceptive flexion reflex (NFR), a marker of spinal nociception. To elicit emotion, 2 blocks of pleasant, neutral, and unpleasant pictures were presented. In block 1, participants were asked to passively view pictures during which painful electric stimulations were delivered to evoke pain and the NFR. Valence, arousal, corrugator electromyogram, and skin conductance response were used to measure emotional responses to pictures. To manipulate emotion regulation, participants were randomized to either suppress (downregulate) or enhance (upregulate) their emotion during block 2 (other procedures same as block 1). Instructions to suppress decreased subjective and physiological responding to emotional pictures, reduced emotional modulation of pain, and generally decreased NFR magnitude (regardless of picture content). Instructions to enhance emotion increased subjective responding to emotional pictures but did not alter physiological responding to pictures or emotional modulation of pain/NFR in predictable ways. Results imply that downregulation/suppression of negative emotions may work best to reduce pain facilitation. Furthermore, this study contributes to the existing literature that shows that pain and pain signaling is tightly coupled with emotional states and that emotion regulation can impact pain perception.