Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique known for its reversibility, high safety, and patient compliance. It holds promise as a potential non-pharmacological method for analgesia. Previous studies have primarily focused on applying tDCS to the dorsolateral prefrontal cortex (DLPFC) or the primary motor cortex (M1) for pain modulation. However, the analgesic effect of tDCS has shown unsatisfactory results with significant variation among individuals, possibly due to the complexity of the pain neural network and the limited targeting of previous tDCS interventions. To improve the efficacy of tDCS in pain relief, the present study used dual-target tDCS technology to simultaneously modulate the DLPFC and M1, with the aim of investigating the analgesic effects and advantages of this approach. In Experiment 1, a total of 80 healthy participants were double-blind, randomly allocated to receive either lDLPFC+rM1-tDCS, lDLPFC-tDCS, rM1-tDCS, or Sham-tDCS. The perception of transient pain induced by thermal stimulation and pressure pain thresholds were assessed before and after tDCS application. Dual-target tDCS demonstrated a significant analgesic effect on low-intensity transient pain and pressure pain thresholds, surpassing the effects observed in the lDLPFC-tDCS or rM1-tDCS groups. Furthermore, we found a significant correlation between the analgesic effects of dual-target tDCS on transient pain and participants' pain fear trait. Specifically, the higher the scores on the participants' fear of pain questionnaire, the greater the analgesic effects. In Experiment 2, a total of 26 participants double-blinded underwent three distinct intervention conditions: lDLPFC+rM1-tDCS (Dual-target), lDLPFC or rM1-tDCS (Single-target), and Sham. The sequence of these conditions was randomized, with a minimum interval of seven days between sessions. The perception of sustained pain induced by capsaicin was assessed during tDCS modulation and 30 minutes post-stimulation. During and after the tDCS modulation, the pain intensity scores in the dual-target tDCS group were significantly lower than those in the sham stimulation group and the single-target tDCS group.

当前经颅直流电刺激(transcranial direct current stimulation, tDCS)的镇痛效果不佳且存在较大的个体差异,可能与疼痛神经网络的复杂性及当前t DCS调控靶点单一有关。为提高t DCS缓解疼痛的效果,本研究使用双盲、随机对照的实验设计,采用双靶点t DCS技术,对背外侧前额叶皮层(dorsolateral prefrontal cortex, DLPFC)和初级运动皮层(primarymotorcortex,M1)进行同步刺激,通过调节DLPFC和M1所属不同的疼痛传导通路,探究双靶点t DCS的镇痛效果及优势。结果表明,与假刺激对照组相比,双靶点t DCS组对中等强度短时热痛、辣椒素诱发的持续性疼痛以及压痛阈限具有显著的调控效应,且调控效应优于单靶点t DCS组。同时,双靶点t DCS的镇痛效应与被试的疼痛恐惧特质显著相关,即被试疼痛恐惧量表评分越高,镇痛效果越好。综上,本研究揭示了双靶点tDCS对短时热痛和持续性疼痛的稳定镇痛效果,支持了疼痛神经网络的并行处理理论,也为双靶点t DCS在疼痛治疗中的潜在应用提供了科学依据。

国家自然科学基金项目(32171078,32322035)