METHODS: To investigate whether methylphenidate (MPH) and transcranial direct current stimulation (tDCS) share common underlying mechanisms and cognitive effects, we administered MPH and anodal tDCS (atDCS) over the right inferior frontal gyrus both separately and combined, while healthy adult participants (n = 104) performed a response selection and inhibition task. The recorded EEG data were analyzed with a focus on theta band activity, and source estimation analyses were conducted.
RESULTS: The behavioral data show that MPH and atDCS revealed interactive effects on the ability to inhibit responses. Both MPH and atDCS modulated task-related theta oscillations in the supplementary motor area when applied separately, making a common underlying mechanism likely. When both stimulation methods were combined, there was no doubling of effects in the supplementary motor area but a shift to inferior frontal areas in the cortical network responsible for theta-driven processing.
CONCLUSIONS: The results indicate that both MPH and atDCS likely share a common underlying neuronal mechanism, and interestingly, they demonstrate interactive effects when combined, which are most likely due to the physical limitations of gain control increases. The current study provides critical groundwork for future combined applications of MPH and non-invasive brain stimulation.
方法:为了调查MPH和tDCS是否具有共同的潜在机制和认知效应,我们分别和联合在右额下回上施用哌醋甲酯(MPH)和阳极tDCS(atDCS),而健康的成年参与者(N=104)执行反应选择和抑制任务。分析记录的EEG数据,重点是θ带活动,并进行源估计分析。
结果:行为数据表明,MPH和atDCS对抑制反应的能力显示出相互作用的影响。当分别应用时,MPH和atDCS都调制了辅助运动区域(SMA)中与任务相关的theta振荡,可能会形成一个共同的潜在机制。当两种刺激方法结合时,SMA没有加倍的效果,而是转移到皮层网络中负责theta驱动处理的下额叶区域。
结论:结果表明,MPH和atDCS可能具有共同的潜在神经元机制,有趣的是,它们结合在一起时表现出互动效果,这很可能是由于增益控制的物理限制而增加。目前的研究为未来MPH和非侵入性脑刺激的联合应用提供了关键的基础。