Department of Rehabilitation, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China.
Department of Physical Medicine and Rehabilitation, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai 519000, China.
Neural Plast. 2020 Oct 19;2020:8820443. doi: 10.1155/2020/8820443. eCollection 2020.
It is generally believed that the placebo response can elicit an analgesic effect, whilst the nocebo response can elicit a hyperalgesia effect in pain. Placebo analgesia and nocebo hyperalgesia effects are increasing concerns for researchers. Growing evidence suggests personality differences have an impact on both placebo and nocebo effects. However, previous studies have not reached a unified conclusion. We designed this study to explore the personality differences of functional magnetic resonance imaging (fMRI) signals in placebo response and nocebo response by using psychophysiological interaction (PPI) analysis. 30 healthy subjects underwent conditioning induction training to establish expectations of placebo effect and nocebo effect, and then, all subjects completed the following experimental procedures: (1) baseline scanning, (2) acute pain model establishment, (3) pain status scanning, and (4) pseudorandom scanning of block design of placebo response or nocebo response. Behavioral data were collected after each scan. The results of this study showed that (1) there were significant differences of VAS placebo intervention between the extrovert group and the introvert group ( = 0.004); (2) there were significant differences of VAS nocebo intervention between the extrovert group and the introvert group ( = 0.011); (3) there were significant differences between the VAS placebo intervention and VAS pain status (baseline) in both the extrovert group ( < 0.001) and the introvert group ( = 0.001); (4) there were significant differences between the VAS nocebo intervention and VAS pain status (baseline) in both the extrovert group ( = 0.008) and the introvert group ( < 0.001). Moreover, there were significant differences in the brain network for placebo and nocebo responses between different personalities. We found that (1) deactivation differences of the pain-related network and limbic system play an important role in personality differences associated with placebo analgesia and (2) differences of control of anxiety and activation of dorsolateral prefrontal cortex may cause the personality differences observed in nocebo hyperalgesia.
人们普遍认为，安慰剂效应可以产生镇痛作用，而反安慰剂效应可以在疼痛中产生痛觉过敏效应。安慰剂镇痛和反安慰剂痛觉过敏效应越来越受到研究人员的关注。越来越多的证据表明，个性差异对安慰剂和反安慰剂效应都有影响。然而，以前的研究并没有得出统一的结论。我们设计了这项研究，通过使用心理生理交互（PPI）分析来探索安慰剂反应和反安慰剂反应中功能性磁共振成像（fMRI）信号的个性差异。30 名健康受试者接受了条件诱导训练，以建立对安慰剂效应和反安慰剂效应的期望，然后所有受试者完成了以下实验程序：（1）基线扫描，（2）急性疼痛模型建立，（3）疼痛状态扫描，和（4）安慰剂反应或反安慰剂反应的随机块设计伪扫描。每次扫描后收集行为数据。该研究结果表明：（1）外向组和内向组之间的 VAS 安慰剂干预有显著差异（ = 0.004）；（2）外向组和内向组之间的 VAS 反安慰剂干预有显著差异（ = 0.011）；（3）外向组（ < 0.001）和内向组（ = 0.001）的 VAS 安慰剂干预与 VAS 疼痛状态（基线）之间存在显著差异；（4）外向组（ = 0.008）和内向组（ < 0.001）的 VAS 反安慰剂干预与 VAS 疼痛状态（基线）之间存在显著差异。此外，不同个性之间的安慰剂和反安慰剂反应的大脑网络存在显著差异。我们发现：（1）疼痛相关网络和边缘系统的去激活差异在与安慰剂镇痛相关的个性差异中起着重要作用，（2）焦虑控制和背外侧前额叶皮质激活的差异可能导致反安慰剂痛觉过敏中观察到的个性差异。
