Recent evidence shows that hippocampal theta oscillations, usually linked to memory and navigation, are also observed during online language processing, suggesting a shared neurophysiological mechanism between language and memory. However, it remains to be established what specific roles hippocampal theta oscillations may play in language, and whether and how theta mediates the communication between the hippocampus and the perisylvian cortical areas, generally thought to support language processing. With whole-head magnetoencephalographic (MEG) recordings, the present study investigated these questions with two experiments. Using a violation paradigm, extensively used for studying neural underpinnings of different aspects of linguistic processing, we found increased theta power (4 - 8 Hz) in the hippocampal formation, when participants read a semantically incorrect vs. correct sentence ending. Such a pattern of results was replicated using different sentence stimuli in another cohort of participants. Importantly, no significant hippocampal theta power increase was found when participants read a semantically correct but syntactically incorrect sentence ending vs. a correct sentence ending. These findings may suggest that hippocampal theta oscillations are specifically linked to lexical-semantic related processing, and not general information processing in sentence reading. Furthermore, we found significantly transient theta phase coupling between the hippocampus and the left superior temporal gyrus, a hub area of the cortical network for language comprehension. This transient theta phase coupling may provide an important channel that links the memory and language systems for the generation of sentence meaning. Overall, these findings help specify the role of hippocampal theta in language, and provide a novel neurophysiological mechanism at the network level that may support the interface between memory and language.

中文翻译：

---

Theta 振荡支持语言和记忆之间的接口

最近的证据表明，通常与记忆和导航相关的海马 theta 振荡在在线语言处理过程中也被观察到，这表明语言和记忆之间存在共享的神经生理机制。然而，海马θ振荡在语言中可能发挥的具体作用还有待确定，以及θ是否以及如何介导海马和侧裂周围皮层区域之间的交流，通常被认为支持语言处理。通过全头脑磁图 (MEG) 记录，本研究通过两个实验调查了这些问题。使用广泛用于研究语言处理不同方面的神经基础的违反范式，我们发现海马体形成中的 theta 功率（4 - 8 Hz）增加，当参与者阅读语义不正确与正确的句子结尾时。在另一组参与者中使用不同的句子刺激复制了这种结果模式。重要的是，当参与者阅读语义正确但句法不正确的句子结尾与正确的句子结尾时，没有发现海马的 theta 功率显着增加。这些发现可能表明海马 theta 振荡与词汇语义相关处理特别相关，而不是句子阅读中的一般信息处理。此外，我们发现海马体和左侧颞上回之间存在显着的瞬态θ相位耦合，这是用于语言理解的皮质网络的枢纽区域。这种短暂的 theta 相位耦合可能为连接记忆和语言系统以生成句子意义提供了一个重要的渠道。总体而言，这些发现有助于明确海马 theta 在语言中的作用，并在网络层面提供一种新的神经生理机制，可能支持记忆和语言之间的接口。