School of Psychology, Shenzhen University, Shenzhen, China.
Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong, China.
Neuroimage. 2022 Nov;263:119599. doi: 10.1016/j.neuroimage.2022.119599. Epub 2022 Aug 29.
Alterations of empathy for others' pain among patients with chronic pain remained inconsistent. Here, applying a capsaicin-based ongoing pain model on healthy participants, this study investigated how ongoing first-hand pain influences empathic reactions to vicarious pain stimuli. Healthy participants were randomly treated with topical capsaicin cream (capsaicin group) or hand cream (control group) on the left forearm. Video clips showing limbs in painful and non-painful situations were used to induce empathic responses. The capsaicin group showed greater empathic neural responses in the right primary somatosensory cortex (S1) than the control group but smaller responses in the left anterior insula (AI) accompanied with smaller empathic pain-intensity ratings. Notably, the intensity of ongoing pain negatively correlated with empathy-related neural responses in the left AI. Inter-subject phase synchronization analysis was used to assess stimulus-dependent dynamic functional connectivity within or between brain regions engaged in pain empathy. The capsaicin group showed greater empathy-related neural synchronization within S1 and between S1 and AI, but less synchronization within AI and between AI and MCC. Behaviorally, the differential inter-subject pain-intensity rating alignment between painful and non-painful videos was more positive for the capsaicin group than for the control group, and this effect was partially mediated by the inter-subject neural synchronization between S1 and AI. These results suggest that ongoing first-hand pain facilitates neural activation and synchronization within brain regions associated with empathy-related somatosensory resonance at the cost of inhibiting activation and synchronization within brain regions engaged in empathy-related affective sharing.
慢性疼痛患者对他人疼痛的同理心变化仍不一致。在此，我们在健康参与者中应用基于辣椒素的持续性疼痛模型，研究持续性第一手疼痛如何影响对替代性疼痛刺激的同理心反应。健康参与者的左前臂被随机涂抹辣椒素乳膏（辣椒素组）或护手霜（对照组）。使用显示肢体处于疼痛和非疼痛情况下的视频片段来诱发同理心反应。与对照组相比，辣椒素组在右侧初级体感皮层（S1）中表现出更强的同理心神经反应，但左侧前岛叶（AI）的反应较小，同时同理心疼痛强度评分也较小。值得注意的是，持续性疼痛的强度与左侧 AI 中与同理心相关的神经反应呈负相关。采用相位同步分析来评估参与疼痛同理心的大脑区域内或区域间与刺激相关的动态功能连接。与对照组相比，辣椒素组在 S1 内和 S1 与 AI 之间表现出更强的与同理心相关的神经同步性，但在 AI 内和 AI 与 MCC 之间的同步性较弱。行为上，与对照组相比，辣椒素组在痛苦和非痛苦视频之间的个体间疼痛强度评分一致性更积极，这种效应部分由 S1 和 AI 之间的个体间神经同步介导。这些结果表明，持续性第一手疼痛促进了与同理心相关的体感共振相关大脑区域的神经激活和同步，而抑制了与同理心相关的情感共享相关大脑区域的激活和同步。
