Shi Yu, Wang Yaping, Zeng Yanyan, Zhan Hongrui, Huang Shimin, Cai Guiyuan, Yang Jianming, Wu Wen
Department of Rehabilitation, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
Department of Physical Medicine and Rehabilitation, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China.
Ann Transl Med. 2021 Mar;9(5):371. doi: 10.21037/atm-20-5123.
Placebo and nocebo responses have been increasingly gaining the attention of clinical and scientific researchers. Inconsistent conclusions from current studies indicate that different factors potentially affect both placebo and nocebo responses. Increasing evidence suggests that personality differences may affect the mechanisms of both two responses. In the present work, we explored the characteristics of neural signals of placebo and nocebo responses based on functional connectivity (FC) analysis and Granger causality analysis (GCA).
A total of 34 healthy participants received conditional induction training to establish placebo and nocebo responses. Every participant completed the following experimental workflow, including scanning of baseline, experimental low back pain model establishment, scanning of acute pain status, and scanning of placebo response or nocebo response. We collect visual analogue scale (VAS) data after each scanning. Functional magnetic resonance imaging (fMRI) data from different personality groups were subjected to FC analysis and multivariate GCA (mGCA).
Pain scores for placebo and nocebo responses were statistically different across different personality. There are also statistically differences in the neural signals of two responses across different personality.
The findings of the present study indicated that extroverted and introverted participants are likely to experience placebo analgesic effects and nocebo hyperalgesia effects, respectively. Both extroverted and introverted participants showed significant changes in brain networks under placebo response. Variation in emotional control and ventromedial prefrontal cortex inactivity may constitute the bulk of the personality differences in placebo analgesia. Differences in the regulation of the sensory conduction system (SCS) and release of the emotional circuit could be important factors affecting personality differences in nocebo hyperalgesia.
安慰剂和反安慰剂效应越来越受到临床和科研人员的关注。当前研究得出的结论并不一致，这表明不同因素可能会影响安慰剂和反安慰剂效应。越来越多的证据表明，人格差异可能会影响这两种效应的机制。在本研究中，我们基于功能连接（FC）分析和格兰杰因果分析（GCA）探讨了安慰剂和反安慰剂效应的神经信号特征。
共有34名健康参与者接受了条件诱导训练，以建立安慰剂和反安慰剂效应。每位参与者完成了以下实验流程，包括基线扫描、实验性下背痛模型建立、急性疼痛状态扫描以及安慰剂效应或反安慰剂效应扫描。每次扫描后我们收集视觉模拟量表（VAS）数据。对来自不同人格组的功能磁共振成像（fMRI）数据进行FC分析和多变量GCA（mGCA）。
不同人格的安慰剂和反安慰剂效应的疼痛评分在统计学上存在差异。两种效应的神经信号在不同人格之间也存在统计学差异。
本研究结果表明，外向型和内向型参与者可能分别会经历安慰剂镇痛效应和反安慰剂痛觉过敏效应。外向型和内向型参与者在安慰剂效应下脑网络均出现了显著变化。情绪控制的差异和腹内侧前额叶皮质的无活动状态可能构成了安慰剂镇痛中人格差异的主要部分。感觉传导系统（SCS）调节和情绪回路释放的差异可能是影响反安慰剂痛觉过敏人格差异的重要因素。
