Li Xiaoyun, Jin Richu, Lu Xuejing, Zhan Yilin, Jiang Naifu, Peng Weiwei
School of Psychology, Shenzhen University, Shenzhen, China.
Tech X Academy, Shenzhen Polytechnic University, Shenzhen, China.
Pain. 2025 May 1;166(5):1157-1166. doi: 10.1097/j.pain.0000000000003452. Epub 2024 Oct 16.
Pain perception is closely tied to the brain's anticipatory processes, particularly involving the suppression of sensorimotor α-oscillations, which reflect the system's readiness for incoming pain. Higher sensorimotor α-oscillation levels are correlated with lower pain sensitivity. Alpha transcranial alternating current stimulation (α-tACS) can enhance these oscillations, potentially reducing pain perception, with effects that may be sustained and influenced by the certainty of pain expectations. Hence, this study investigated the immediate and sustained effects of α-tACS on pain anticipation and perception, focusing on how these effects are shaped by the certainty of expectations. In a double-blind, sham-controlled design, 80 healthy participants underwent a 20-minute session of real or sham α-tACS over the right sensorimotor region. Behavioral and neural responses related to pain anticipation and perception were recorded before, immediately after, and 30 minutes poststimulation under both certain and uncertain conditions. Compared with sham stimulation, real α-tACS disrupted the habituation of laser-evoked potentials (N2-P2 complex), particularly under certain expectations, with effects persisting 30 minutes poststimulation. In anticipatory brain oscillations, real α-tACS enhanced somatosensory α1-oscillations and increased midfrontal θ-oscillations in conditions of certainty, with θ-oscillation modulation showing sustained effects. Mediation analysis revealed that α-tACS reduced pain reactivity by enhancing somatosensory α1-oscillations but increased pain reactivity through the enhancement of midfrontal θ-oscillations, with the latter effect being more pronounced. These findings suggest that while α-tACS may provide pain relief through somatosensory α-oscillation augmentation, its stronger and longer-lasting impact on midfrontal θ-oscillations could lead to hyperalgesia, particularly in the context of certain pain expectations.
疼痛感知与大脑的预期过程密切相关，特别是涉及感觉运动α振荡的抑制，这种振荡反映了系统对即将到来的疼痛的准备状态。较高的感觉运动α振荡水平与较低的疼痛敏感性相关。经颅交流电刺激（α-tACS）可以增强这些振荡，有可能降低疼痛感知，其效果可能会持续，并受到疼痛预期确定性的影响。因此，本研究调查了α-tACS对疼痛预期和感知的即时和持续影响，重点关注这些影响如何受预期确定性的影响。在一项双盲、假刺激对照设计中，80名健康参与者在右侧感觉运动区域接受了20分钟的真实或假α-tACS治疗。在确定和不确定条件下，分别在刺激前、刺激后立即以及刺激后30分钟记录与疼痛预期和感知相关的行为和神经反应。与假刺激相比，真实的α-tACS破坏了激光诱发电位（N2-P2复合体）的习惯化，特别是在确定预期的情况下，刺激后30分钟效果仍然存在。在预期性脑振荡中，真实的α-tACS在确定条件下增强了体感α1振荡并增加了额中θ振荡，θ振荡调制显示出持续的效果。中介分析表明，α-tACS通过增强体感α1振荡降低了疼痛反应性，但通过增强额中θ振荡增加了疼痛反应性，后一种效应更为明显。这些发现表明，虽然α-tACS可能通过增强体感α振荡来缓解疼痛，但其对额中θ振荡更强、更持久的影响可能导致痛觉过敏，特别是在确定的疼痛预期背景下。
