Research progress on the mechanisms of pain empathy

Abstract

Recent research has highlighted the indispensability of traditional molecular biology and imaging techniques in pain research. However, the mechanisms underlying pain empathy remain unclear. Consequently, a deeper understanding of these mechanisms would greatly enhance pain management. This article aimed to scrutinize previous research findings on pain empathy, with a particular emphasis on the correlation between empathy for pain and distinct anatomical structures, such as mirror neurons, the anterior cingulate cortex, insular cortex, prefrontal cortex, and amygdala. Additionally, this study explored the involvement of endogenous systems, including oxytocin and the locus coeruleus norepinephrine system, hypothalamic-pituitary-adrenal axis, opioid system, and 5-hydroxylamine signaling. In conclusion, the mechanisms of pain empathy are complex and diverse, and research on pain empathy and target treatment will contribute to pain treatment.

Keywords: empathic response; mirror neurons; neural mechanisms; pain; pain empathy.

Figure 1

Three tiers are present within the pain matrix. Perception and localization of pain are influenced by the primary cortical pain matrix, which consists of the S1, S2, parietal operculum, and thalamus; the ACC, INS, AMY, and hippocampus comprise the secondary cortical pain matrix, which is responsible for empathy for suffering; the third region, which includes the PFC, MCC, and PCC, is linked to cognition. ACC, anterior cingulate cortex; AMY, amygdala; INS, insula; MCC, medial cingulate cortex; PCC, posterior cingulate cortex; PFC, prefrontal cortex; S1, primary somatosensory cortex; S2, secondary somatosensory cortex. [Color figure can be viewed at wileyonlinelibrary.com]

Figure 2

Schematic of areas in the human brain that contain mirror neurons (inferior parietal lobule and inferior frontal gyrus) and make up the “core” system. The “extended” mirror neuron system (anatomical and functional circuits) involves additional brain areas, e.g., anterior cingulate cortex, amygdala, insula, prefrontal cortex, superior temporal sulcus, and middle temporal gyrus; functional perspectives propose that one critical component of the “extended” mirror neuron system is the sensorimotor cortex. Oxytocin, the LC/NE system, the HPA axis, the opioid system, and 5‐hydroxytryptamine are regulators in the “extended” mirror neuron system. The “extended” mirror neuron system connects to the core system and performs transformations on the data critical for mirroring and pain simulation. HPA, hypothalamus–pituitary–adrenal; LC/NE, locus coeruleus–norepinephrine; MNS, mirror neuron system. [Color figure can be viewed at wileyonlinelibrary.com]