INTRODUCTION Previous work in the language domain has shown that 10 Hz rTMS of the left or right posterior inferior frontal gyrus (pIFG) in the prefrontal cortex impaired phonological decision-making, arguing for a causal contribution of the bilateral pIFG to phonological processing. However, the neurophysiological correlates of these effects are unclear. The present study addressed the question whether neural activity in the prefrontal cortex could be modulated by 10 Hz tACS and how this would affect phonological decisions. METHODS In three sessions, 24 healthy participants received tACS at 10 Hz or 16.18 Hz (control frequency) or sham stimulation over the bilateral prefrontal cortex before task processing. Resting state EEG was recorded before and after tACS. We also recorded EEG during task processing. RESULTS Relative to sham stimulation, 10 Hz tACS significantly facilitated phonological response speed. This effect was task-specific as tACS did not affect a simple control task. Moreover, 10 Hz tACS significantly increased theta power during phonological decisions. The individual increase in theta power was positively correlated with the behavioral facilitation after 10 Hz tACS. CONCLUSION Our results show a facilitation of phonological decisions after 10 Hz tACS over the bilateral prefrontal cortex. This might indicate that 10 Hz tACS increased task-related activity in the stimulated area to a level that was optimal for phonological performance. The significant correlation with the individual increase in theta power suggests that the behavioral facilitation might be related to increased theta power during language processing.

中文翻译：

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前额叶皮层 10 Hz tACS 对语音词决定的后效

引言 先前在语言领域的工作表明，前额叶皮层中左或右后额下回 (pIFG) 的 10 Hz rTMS 会损害语音决策，认为双侧 pIFG 对语音处理有因果贡献。然而，这些影响的神经生理学相关性尚不清楚。本研究解决了前额叶皮层中的神经活动是否可以通过 10 Hz tACS 进行调节以及这将如何影响语音决策的问题。方法 在三个疗程中，24 名健康参与者在任务处理前接受 10 Hz 或 16.18 Hz（控制频率）的 tACS 或双侧前额叶皮层的假刺激。在 tACS 之前和之后记录静息状态 EEG。我们还在任务处理过程中记录了 EEG。结果 相对于假刺激，10 Hz tACS 显着促进了语音响应速度。这种效果是特定于任务的，因为 tACS 不影响简单的控制任务。此外，10 Hz tACS 在语音决策过程中显着增加了 theta 功率。在 10 Hz tACS 后，θ 功率的个体增加与行为促进呈正相关。结论 我们的结果表明，在 10 Hz tACS 后双侧前额叶皮层上的语音决策有促进作用。这可能表明 10 Hz tACS 将受刺激区域中与任务相关的活动增加到最适合语音性能的水平。与个体 theta 功率增加的显着相关性表明行为促进可能与语言处理过程中增加的 theta 功率有关。