Little is known about how transcranial alternating current stimulation (tACS) interacts with brain activity. Here, we investigate the effects of tACS using an intermittent tACS-EEG protocol and use, in addition to classical metrics, Lempel-Ziv-Welch complexity (LZW) to characterize the interactions between task, endogenous and exogenous oscillations. In a cross-over study, EEG was recorded from thirty participants engaged in a change-of-speed detection task while receiving multichannel tACS over the visual cortex at 10 Hz, 70 Hz and a control condition. In each session, tACS was applied intermittently during 5 s events interleaved with EEG recordings over multiple trials. We found that, with respect to control, stimulation at 10 Hz ([Formula: see text]) enhanced both [Formula: see text] and [Formula: see text] power, [Formula: see text]-LZW complexity and [Formula: see text] but not [Formula: see text] phase locking value with respect to tACS onset ([Formula: see text]-PLV, [Formula: see text]-PLV), and increased reaction time (RT). [Formula: see text] increased RT with little impact on other metrics. As trials associated with larger [Formula: see text]-power (and lower [Formula: see text]-LZW) predicted shorter RT, we argue that [Formula: see text] produces a disruption of functionally relevant fast oscillations through an increase in [Formula: see text]-band power, slowing behavioural responses and increasing the complexity of gamma oscillations. Our study highlights the complex interaction between tACS and endogenous brain dynamics, and suggests the use of algorithmic complexity inspired metrics to characterize cortical dynamics in a behaviorally relevant timescale.

中文翻译：

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视觉任务期间的间歇性tACS影响神经振荡和LZW复杂性。

关于经颅交流电刺激（tACS）与大脑活动如何相互作用所知甚少。在这里，我们调查使用间歇性tACS-EEG协议的tACS的影响，除经典指标外，还使用Lempel-Ziv-Welch复杂度（LZW）来表征任务，内源性和外源性振荡之间的相互作用。在一项交叉研究中，记录了30名参与速度变化检测任务的参与者的脑电图，同时在10 Hz，70 Hz和控制条件下通过视觉皮层接收多通道tACS。在每个疗程中，tACS在5 s事件中间歇应用，与多个试验中的EEG记录交错。我们发现，相对于控制而言，以10 Hz刺激（[公式：参见文字]）可以增强[公式：参见文字]和[公式：参见文字]的功率，[公式：参见文本] -LZW复杂度和[公式：参见文本]，而不是[公式：参见文本]关于tACS发作的相位锁定值（[公式：参见文本] -PLV，[公式：参见文本] -PLV），以及增加反应时间（RT）。[公式：请参见文字]增加了RT，对其他指标的影响很小。由于与更大[功率]和更低[功率] [LZW]相关的试验预测较短的RT，因此我们认为[功率：[Low]]会通过增加电流来扰乱功能相关的快速振荡。 [公式：参见文字]频带功率，减慢行为响应并增加伽玛振荡的复杂性。我们的研究突出了tACS与内源性大脑动力学之间的复杂相互作用，并建议使用算法复杂性启发性指标来在行为相关的时间尺度内表征皮层动力学。