ERP Indicators of Self-Pain and Other Pain Reductions due to Placebo Analgesia Responding: The Moderating Role of the Fight-Flight-Freeze System.

Arianna Vecchio,Vilfredo De Pascalis

doi:10.3390/brainsci11091192

Abstract

This study evaluates the modulation of phasic pain and empathy for pain induced by placebo analgesia during pain and empathy for pain tasks. Because pain can be conceptualized as a dangerous stimulus that generates avoidance, we evaluated how approach and avoidance personality traits modulate pain and empathy for pain responses. We induced placebo analgesia to test whether this also reduces self-pain and other pain. Amplitude measures of the N1, P2, and P3 ERPs components, elicited by electric stimulations, were obtained during a painful control, as well as during a placebo treatment expected to induce placebo analgesia. The placebo treatment produced a reduction in pain and unpleasantness perceived, whereas we observed a decrease in the empathy unpleasantness alone during the empathy pain condition. The moderator effects of the fight-flight-freeze system (FFFS) in the relationships linking P2 and P3 amplitude changes with pain reduction were both significant among low to moderate FFFS values. These observations are consistent with the idea that lower FFFS (active avoidance) scores can predict placebo-induced pain reduction. Finally, in line with the revised Reinforcement Sensitivity Theory (r-RST), we can assume that phasic pain is an aversive stimulus activating the active-avoidance behavior to bring the system back to homeostasis.

Highlights

Pain is a complex psychophysical phenomenon characterized by unpleasant sensory and emotional experience in which the sensorial-discriminative component of a complex system of nerve circuits [1], defined as the pain matrix [2,3,4], is occasionally not necessary to generate this complex phenomenon [5]
The placebo treatment produced a reduction in pain and unpleasantness perceived, whereas we observed a decrease in the empathy unpleasantness alone during the empathy pain condition
González-Franco [61] reproduced the findings reported by Meng and colleagues [57], Li and Han [58], and Fan and Han [59] in a virtual reality simulation, in which participants experienced a virtual threat on their backhand

Summary

Introduction

Pain is a complex psychophysical phenomenon characterized by unpleasant sensory and emotional experience in which the sensorial-discriminative component of a complex system of nerve circuits [1], defined as the pain matrix [2,3,4], is occasionally not necessary to generate this complex phenomenon [5]. Because pain is a subjective and individual experience, it is sometimes difficult to discriminate the unpleasant component of the noxious stimulus from a painful one. In terms of approach and avoidance motivational personality traits, pain can be conceptualized as a powerful, dangerous stimulus that generates behavioral avoidance. Research has suggested that motivational personality traits [13] are the psychological factors that play an essential role in pain reduction induced by placebo treatment [14]. One of the most famous neuroscience theories of personality is the Revised Reinforcement Sensitivity Theory (r-RST) [18,19,20,21]

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Conclusion