Pharmacological fMRI provides evidence for opioidergic modulation of discrimination of facial pain expressions

Abstract

The endogenous opioid system is strongly involved in the modulation of pain. However, the potential role of this system in perceiving painful facial expressions from others has not been sufficiently explored as of yet. To elucidate the contribution of the opioid system to the perception of painful facial expressions, we conducted a double‐blind, within‐subjects pharmacological functional magnetic resonance imaging (fMRI) study, in which 42 participants engaged in an emotion discrimination task (pain vs. disgust expressions) in two experimental sessions, receiving either the opioid receptor antagonist naltrexone or an inert substance (placebo). On the behavioral level, participants less frequently judged an expression as pain under naltrexone as compared to placebo. On the neural level, parametric modulation of activation in the (putative) right fusiform face area (FFA), which was correlated with increased pain intensity, was higher under naltrexone than placebo. Regression analyses revealed that brain activity in the right FFA significantly predicted behavioral performance in disambiguating pain from disgust, both under naltrexone and placebo. These findings suggest that reducing opioid system activity decreased participants' sensitivity for facial expressions of pain, and that this was linked to possibly compensatory engagement of processes related to visual perception, rather than to higher level affective processes, and pain regulation.

Neural dynamics between anterior insular cortex and right supramarginal gyrus dissociate genuine affect sharing from perceptual saliency of pretended pain

“…It was thus one major aim of our study to address this question. In this respect, contextual factors, individuals' appraisals, and attentional processes would all impact their exact response to the affective states of others (Gu & Han, 2007;Hein & Singer, 2008, for review; Lamm et al, 2010;Forbes & Hamilton, 2020;Zhao et al, 2021). Recently, Coll et al (2017) have thus proposed a framework that attempts to capture these influences on affect sharing and empathic responses.…”

Chronic non‐medical prescription opioid use and empathy for pain: Does pain make the difference?

“…This association was not explained by craving although we found a high correlation between RMSSD‐HRV and craving as in our previous study, where low opioid craver showed stronger emotion regulation indexed by higher RMSSD‐HRV during social pain (i.e., social exclusion) compared to high opioid craver. A recent study using a MOR antagonist showed that a decreased activity of the MOR system resulted in lower discrimination of facial pain expressions (Zhao et al., 2020). These findings suggest that an increased activity of the MOR system might enhance the sensitivity for painful facial expression.…”

Effective connectivity reveals distinctive patterns in response to others’ genuine affective experience of disgust as compared to pain

“…Among the array of aversive experiences, the emotion of disgust partially overlaps with pain regarding its neural mechanisms (Corradi-Dell’Acqua et al, 2016). Also, disgust and pain share similarities with respect to their facial expression (Zhao et al, 2021a) and are similarly important for survival and somatic protection (Sharvit et al, 2015; Sharvit et al, 2020). Particularly, research using multi-voxel pattern analysis (MVPA) shows overlapping brain maps in aIns and aMCC not only for self-experienced but also vicarious experiences of pain and disgust, suggesting a modality-independent representation of the unpleasantness shared by self-experienced aversive affect and empathy for such affect (Corradi-Dell’Acqua et al, 2016).…”

“…Among the array of aversive experiences, the emotion of disgust partially overlaps with pain regarding its neural mechanisms (Corradi-Dell'Acqua et al, 2016). Also, disgust and pain share similarities with respect to their facial expression (Zhao et al, 2021a) and are similarly important for survival and somatic protection (Sharvit et al, 2015;Sharvit et al, 2020).…”