Peng Weiwei, Zhan Yilin, Jin Richu, Lou Wutao, Li Xiaoyun
School of Psychology, Shenzhen University, Shenzhen, Guangdong, China.
Department of Computer Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, China.
Pain. 2023 Jun 1;164(6):1280-1290. doi: 10.1097/j.pain.0000000000002814. Epub 2022 Oct 26.
Transcranial alternating current stimulation (tACS) is believed to modulate brain oscillations in a frequency-specific manner. Given the correlation between sensorimotor α-oscillations and pain perception, tACS that targets sensorimotor α-oscillations has the potential to reduce pain. Therefore, this study sought to determine the aftereffects of α-tACS over unilateral primary sensorimotor cortex (SM1) on the perceptual and neural responses to noxious painful stimulation of the contralateral hand. Using a double-blinded and sham-controlled design, 60 healthy participants were recruited to receive either α-tACS or sham stimulation of unilateral SM1 through an electrode montage in a 4 × 1 ring configuration. Neural responses to laser nociceptive stimuli were assessed using functional magnetic resonance imaging immediately before and after α-tACS intervention. Perceptual reports were recorded simultaneously. Compared with sham stimulation, α-tACS attenuated bilateral SM1 responses to painful stimuli delivered to the contralateral hand. Although α-tACS did not exert direct effect on subjective pain perception, it can indirectly decrease ratings of pain perception by reducing brain activity within the targeted SM1. Moreover, α-tACS decreased the functional connectivity between the targeted SM1 and a network of regions that are crucially involved in pain processing, including the middle cingulate cortex, contralateral somatosensory cortex, and dorsolateral prefrontal cortex. These results demonstrated that after α-tACS applied over the unilateral SM1 does attenuate subsequent neural processing of pain within bilateral sensorimotor regions as well as sensorimotor functional connectivity. The findings provide evidence that sensorimotor α-oscillations directly affect pain processing and support the application of sensorimotor α-tACS for inducing pain analgesia.
经颅交流电刺激（tACS）被认为能以频率特异性方式调节脑振荡。鉴于感觉运动α振荡与疼痛感知之间的相关性，靶向感觉运动α振荡的tACS有可能减轻疼痛。因此，本研究旨在确定单侧初级感觉运动皮层（SM1）上的α-tACS对患侧手有害疼痛刺激的感知和神经反应的后续影响。采用双盲和假刺激对照设计，招募了60名健康参与者，通过4×1环形配置的电极蒙太奇接受单侧SM1的α-tACS或假刺激。在α-tACS干预前后，立即使用功能磁共振成像评估对激光伤害性刺激的神经反应。同时记录感知报告。与假刺激相比，α-tACS减弱了双侧SM1对传递到患侧手的疼痛刺激的反应。虽然α-tACS对主观疼痛感知没有直接影响，但它可以通过减少目标SM1内的脑活动间接降低疼痛感知评分。此外，α-tACS降低了目标SM1与包括中扣带回皮层、对侧体感皮层和背外侧前额叶皮层在内的、在疼痛处理中起关键作用的区域网络之间的功能连接。这些结果表明，单侧SM1上施加α-tACS后确实会减弱双侧感觉运动区域内随后的疼痛神经处理以及感觉运动功能连接。这些发现提供了证据，表明感觉运动α振荡直接影响疼痛处理，并支持应用感觉运动α-tACS诱导疼痛镇痛。
