Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, People's Republic of China.
Institute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, People's Republic of China.
J Neural Eng. 2021 Dec 28;18(6). doi: 10.1088/1741-2552/ac3ef3.
There has become of increasing interest in transcranial alternating current stimulation (tACS) since its inception nearly a decade ago. tACS in modulating brain state is an active area of research and has been demonstrated effective in various neuropsychological and clinical domains. In the visual domain, much effort has been dedicated to brain rhythms and rhythmic stimulation, i.e. tACS. However, less is known about the interplay between the rhythmic stimulation and visual stimulation.Here, we used steady-state visual evoked potential (SSVEP), induced by flickering driving as a widely used technique for frequency-tagging, to investigate the aftereffect of tACS in healthy human subjects. Seven blocks of 64-channel electroencephalogram were recorded before and after the administration of 20min 10Hz tACS, while subjects performed several blocks of SSVEP tasks. We characterized the physiological properties of tACS aftereffect by comparing and validating the temporal, spatial, spatiotemporal and signal-to-noise ratio (SNR) patterns between and within blocks in real tACS and sham tACS.Our result revealed that tACS boosted the 10Hz SSVEP significantly. Besides, the aftereffect on SSVEP was mitigated with time and lasted up to 5 min.Our results demonstrate the feasibility of facilitating the flickering driving by external rhythmic stimulation and open a new possibility to alter the brain state in a direction by noninvasive transcranial brain stimulation.
自近十年前问世以来，经颅交流电刺激（tACS）引起了越来越多的关注。tACS 调节大脑状态是一个活跃的研究领域，已在各种神经心理学和临床领域证明有效。在视觉领域，人们投入了大量精力研究脑节律和节律刺激，即 tACS。然而，对于节律刺激与视觉刺激之间的相互作用知之甚少。在这里，我们使用闪烁驱动诱导的稳态视觉诱发电位（SSVEP）作为频率标记的广泛使用技术，研究健康人类受试者中 tACS 的后效。在给予 20 分钟 10Hz tACS 之前和之后，记录了七组 64 通道脑电图，同时受试者进行了几轮 SSVEP 任务。我们通过比较和验证真实 tACS 和假 tACS 中组内和组间的时间、空间、时空和信噪比（SNR）模式，来描述 tACS 后效的生理特性。我们的结果表明，tACS 显著增强了 10Hz 的 SSVEP。此外，SSVEP 的后效随着时间的推移而减轻，持续时间长达 5 分钟。我们的结果证明了通过外部节律刺激促进闪烁驱动的可行性，并为通过非侵入性经颅脑刺激改变大脑状态的方向开辟了新的可能性。
