Mourkojannis Carla, Wolf Maren-Isabel, Wittkamp Christoph A, Rose Michael
Department of Systems Neuroscience, University Medical Center Hamburg‑Eppendorf, Martinistr. 52, Building W34, 20248, Hamburg, Germany.
Sci Rep. 2025 Aug 27;15(1):31588. doi: 10.1038/s41598-025-17276-8.
Pain perception is an individual and complex process, influenced by biological, social, and psychological factors via top-down modulatory pathways. One factor which plays an important role in pain perception is expectations, which have been popularly examined in placebo and Hyperalgesia studies, showing that pain perception can be modulated by manipulating expectations of treatments, pain stimuli or outcome. This preregistered EEG study provides compelling evidence for the high efficacy of self-generated expectation in modulating pain perception in direct comparison to externally induced expectation in a typical placebo paradigm. 42 participants were asked to generate expectations based on visual cues towards a subsequent pain stimulus and either lighten, enhance, or not actively influence their pain expectation. The behavioural results showed that pain perception was significantly altered by self-generated expectations, and that all three conditions differed significantly from each other regarding the reported pain. Notably, self-regulation produced more pronounced effects than externally induced expectations in direct comparison to the results of a previous placebo interventions using the identical experimental layout, indicating that deception is unnecessary for effective pain modulation. EEG analyses revealed differential neural processing among conditions, particularly within gamma-band activity linked to pain perception, underscoring the influence of self-generated expectations on neural responses. These findings provide evidence that even expectations created on a voluntary basis directly influence pain perception, and that manipulating strategies used in placebo studies such as conditioning, verbal instructions and observational learning may not be necessary to evoke the described effects.
疼痛感知是一个因人而异且复杂的过程，受到生物、社会和心理因素通过自上而下的调节通路的影响。在疼痛感知中起重要作用的一个因素是预期，这在安慰剂和痛觉过敏研究中已得到广泛研究，表明通过操纵对治疗、疼痛刺激或结果的预期可以调节疼痛感知。这项预先注册的脑电图研究提供了令人信服的证据，表明与典型安慰剂范式中的外部诱导预期相比，自我产生的预期在调节疼痛感知方面具有很高的功效。42名参与者被要求根据视觉线索对随后的疼痛刺激产生预期，并减轻、增强或不积极影响他们的疼痛预期。行为结果表明，自我产生的预期显著改变了疼痛感知，并且在报告的疼痛方面，所有三种情况彼此之间存在显著差异。值得注意的是，与之前使用相同实验布局的安慰剂干预结果直接比较，自我调节产生的效果比外部诱导的预期更明显，这表明欺骗对于有效的疼痛调节并非必要。脑电图分析揭示了不同条件下的神经处理差异，特别是在与疼痛感知相关的伽马波段活动中，强调了自我产生的预期对神经反应的影响。这些发现提供了证据，表明即使是基于自愿产生的预期也会直接影响疼痛感知，并且安慰剂研究中使用的操纵策略，如条件作用、言语指令和观察学习，可能并非引发所述效果所必需的。
