A causal role for the precuneus in network-wide theta and gamma oscillatory activity during complex memory retrieval

Complex memory of personal events is thought to depend on coordinated reinstatement of cortical representations by the medial temporal lobes (MTL). MTL-cortical theta and gamma coupling is believed to mediate such coordination, but which cortical structures are critical for retrieval and how they influence oscillatory coupling is unclear. We used magnetoencephalography (MEG) combined with continuous theta burst stimulation (cTBS) to (i) clarify the roles of theta and gamma oscillations in network-wide communication during naturalistic memory retrieval, and (ii) understand the causal relationship between cortical network nodes and oscillatory communication. Retrieval was associated with MTL-posterior neocortical theta phase coupling and theta-gamma phase-amplitude coupling relative to a rest period. Precuneus cTBS altered MTL-neocortical communication by modulating theta and gamma oscillatory coupling. These findings provide a mechanistic account for MTL-cortical com munication and demo...人们普遍认为，个人事件的复杂记忆依赖于内侧颞叶（medial temporal lobes, MTL）对皮层表征的协同恢复。学界认为，MTL-皮层theta与gamma耦合介导了这类协同过程，但目前尚不清楚哪些皮层结构对记忆提取至关重要，以及它们如何影响振荡耦合。我们采用脑磁图（magnetoencephalography, MEG）结合连续theta爆发刺激（continuous theta burst stimulation, cTBS）开展研究，旨在（i）阐明自然情境下记忆提取过程中，theta与gamma振荡在全脑网络通讯中的作用；（ii）解析皮层网络节点与振荡通讯之间的因果关系。与静息期相比，记忆提取伴随MTL-后新皮层theta相位耦合以及theta-gamma相位振幅耦合的增强。楔前叶cTBS通过调节theta与gamma振荡耦合，改变了MTL-新皮层的通讯模式。本研究结果为MTL-皮层的通讯机制提供了机制性阐释，并展示了……