多焦点经颅直流电刺激激活运动皮层对骑行耐力表现的影响

Effects of Multifocal Transcranial Direct Current Stimulation Specifically Activating the Motor Cortex on Cycling Endurance Performance

目的:以前额叶皮层和运动皮层为目标脑区,在健康人群中探索多焦点经颅直流电刺激(transcranial direct current stimulation,tDCS)同时刺激多脑区对骑行耐力表现的影响。方法:受试者在功率自行车上进行递增负荷耐力运动,期间采用功能性近红外光谱脑成像系统监测目标皮层运动终止时的血流动力学表现,通过分析皮层激活与运动时间的相关性确定目标脑区。其后采用多焦点tDCS针对性刺激目标脑区,分析和比较刺激前后最后阶段运动表现和下肢肌肉均方根振幅(root mean square amplitude,RMS),评估刺激干预对骑行耐力表现的影响。结果:1)前额叶皮层和运动皮层在运动终止时大面积激活,其中运动皮层FC1h、FC2h、C1h和C2h的激活与运动时间显著负相关。2)相比刺激前,运动中的心率在多焦点tDCS刺激后显著降低;相比Sham组,多焦点tDCS刺激显著提高运动的做功量和骑行转速。3)推进期,相比刺激前,股直肌、股四头肌内侧、股四头肌外侧和胫骨前肌的RMS在多焦点tDCS刺激后显著降低;相比Sham组,多焦点tDCS组股二头肌RMS在刺激后呈现低的激活水平。提拉期,相比刺激前,股二头肌RMS在多焦点tDCS刺激后显著降低;相比Sham组,多焦点tDCS组股四头肌内侧的RMS在刺激后呈现高的激活水平,腓肠肌外侧RMS在刺激后呈现低的激活水平。结论:多焦点tDCS特异性激活运动皮层提高了骑行耐力表现和机体对运动的适应性,多焦点tDCS可能是增强耐力运动表现的一种有效手段。

Objective:This study examined how endurance cycling performance was affected by multifocal transcranial direct current stimulation(tDCS)that simultaneously stimulates the prefrontal cortex and motor cortex.Methods:Functioning near-infrared spectroscopy was used to monitor hemodynamic responses in the PFC and motor cortex to identify the target cortical regions while participants performed incremental exercise test on a cycling ergometer.Subsequently,multifocal tDCS was used to stimulate these regions,the effects of stimulation were assessed by recording the lower-limb root mean square amplitude(RMS)and cycling performance.Results:1)There were significant correlations between cycling time and FC1h,FC2h,C1h and C2h in motor cortex;2)after multifocal tDCS,heart rate significantly decreased compared with before stimulation,while mechanical work and cycling speed increased compared with Sham;3)during the propulsion phase,RMS of the rectus femoris,vastus medialis(VM),vastus lateralis,and tibialis anterior decreased following multifocal tDCS compared to pre-stimulation levels,while RMS of the biceps femoris showed significant lower activation compared with Sham;during the pulling phase,RMS of the biceps femoris significantly decreased following multifocal tDCS,while compared with Sham group,the RMS of vastus medialis showed significantly higher activation and the RMS of gastrocnemius lateralis showed significantly lower activation.Conclusions:Multifocal tDCS specifically activating the motor cortex improves cycling endurance performance and enhances adaptability to training regime,indicating its effectiveness as an augmentation method to increase endurance exercise performance.