Department of Anesthesiology, Shenzhen Samii Medical Center, Guangdong Province, China.
CAS Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing, China; CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
Neuroimage. 2024 Oct 15;300:120877. doi: 10.1016/j.neuroimage.2024.120877. Epub 2024 Sep 29.
Pain is a highly subjective and multidimensional experience, significantly influenced by various psychological factors. Placebo analgesia and nocebo hyperalgesia exemplify this influence, where inert treatments result in pain relief or exacerbation, respectively. While extensive research has elucidated the psychological and neural mechanisms behind these effects, most studies have focused on transient pain stimuli. To explore these mechanisms in the context of tonic pain, we conducted a study using a 15-minute tonic muscle pain induction procedure, where hypertonic saline was infused into the left masseter of healthy participants. We collected real-time Visual Analogue Scale (VAS) scores and functional magnetic resonance imaging (fMRI) data during the induction of placebo analgesia and nocebo hyperalgesia via conditioned learning. Our findings revealed that placebo analgesia was more pronounced and lasted longer than nocebo hyperalgesia. Real-time pain ratings correlated significantly with neural activity in several brain regions. Notably, the putamen was implicated in both effects, while the caudate and other regions were differentially involved in placebo and nocebo effects. These findings confirm that the tonic muscle pain paradigm can be used to investigate the mechanisms of placebo and nocebo effects and indicate that placebo analgesia and nocebo hyperalgesia may have more distinct than common neural bases.
疼痛是一种高度主观和多维的体验，受多种心理因素的显著影响。安慰剂镇痛和反安慰剂痛觉过敏就是这种影响的例证，其中惰性治疗分别导致疼痛缓解或加重。虽然广泛的研究已经阐明了这些效应背后的心理和神经机制，但大多数研究都集中在短暂的疼痛刺激上。为了在紧张性疼痛的背景下探索这些机制，我们使用 15 分钟的紧张性肌肉疼痛诱导程序进行了一项研究，在该程序中，将高渗盐水注入健康参与者的左侧咬肌。我们在通过条件学习诱导安慰剂镇痛和反安慰剂痛觉过敏时收集了实时视觉模拟量表（VAS）评分和功能磁共振成像（fMRI）数据。我们的发现表明，安慰剂镇痛比反安慰剂痛觉过敏更明显且持续时间更长。实时疼痛评分与几个脑区的神经活动显著相关。值得注意的是，纹状体在这两种效应中都有涉及，而尾状核和其他区域则在安慰剂和反安慰剂效应中存在差异。这些发现证实，紧张性肌肉疼痛范式可用于研究安慰剂和反安慰剂效应的机制，并表明安慰剂镇痛和反安慰剂痛觉过敏可能具有比共同神经基础更明显的特征。
