ABSTRACT

We tested the role of hypnotic suggestibility, involuntariness, pain expectation, and subjective hypnotic depth in the prediction of placebo analgesia (PA) responsiveness. We also tested the link of lower and upper alpha sub-band (i.e., ‘alpha1ʹ and ‘alpha2ʹ) power changes with tonic PA responding during waking and hypnosis conditions. Following an initial PA manipulation condition, we recorded EEG activity during waking and hypnosis under two treatments: (1) painful stimulation (Pain); (2) painful stimulation after application of a PA cream. Alpha1 and alpha2 power were derived using the individual alpha frequency method. We found that (1) PA in both waking and hypnosis conditions significantly reduced relative pain perception; (2) during waking, all the above mentioned contextual measures were associated with pain reduction, while involuntariness alone was associated with pain reduction within hypnosis. Enhanced alpha2 power at the left-parietal lead was solely associated with pain reduction in waking, but not in hypnosis condition. Using multiple regression and mediation analyses we found that: (i) during waking, the enhancement of relative left-parietal alpha2 power, directly influenced the enhancement in pain reduction, and, indirectly, through the mediating positive effect of involuntariness; (j) during hypnosis, the enhancement of left-temporoparietal alpha2 power, through the mediation of involuntariness, influenced pain reduction. Current findings obtained during waking suggest that enhanced alpha2 power may serve as a direct-objective measure of the subjective reduction of tonic pain in response to PA treatment. Overall, our findings suggest that placebo analgesia during waking and hypnosis involves different processes of top-down regulation.

摘要

我们测试了催眠暗示性、非自愿性、疼痛预期和主观催眠深度在预测安慰剂镇痛 (PA) 反应性中的作用。我们还测试了低和高 alpha 子带（即“alpha1”和“alpha2”）功率变化与清醒和催眠状态下强直 PA 响应的链接。在初始 PA 操作条件下，我们记录了两种治疗下清醒和催眠期间的 EEG 活动：（1）疼痛刺激（Pain）；(2) 涂抹 PA 霜后的疼痛刺激。Alpha1 和 alpha2 功率是使用单独的 alpha 频率方法得出的。我们发现（1）清醒和催眠状态下的 PA 显着降低了相对疼痛感知；(2) 在醒来时，所有上述上下文措施都与减轻疼痛有关，而在催眠过程中，不由自主与疼痛减轻有关。左顶叶导联增强的 alpha2 功率仅与清醒时疼痛减轻有关，但与催眠状态无关。使用多元回归和中介分析我们发现：（i）在清醒期间，相对左顶叶α2功率的增强，直接影响疼痛减轻的增强，并通过不随意的中介作用间接影响；(j) 在催眠期间，左颞顶α2 能量的增强，通过非自愿的中介，影响疼痛减轻。当前在清醒期间获得的研究结果表明，增强的 alpha2 功率可以作为对 PA 治疗引起的强直性疼痛主观减轻的直接客观测量。总体，