Violante Ines R, Li Lucia M, Carmichael David W, Lorenz Romy, Leech Robert, Hampshire Adam, Rothwell John C, Sharp David J
The Computational, Cognitive and Clinical Neuroimaging Laboratory, Department of Medicine, Imperial College London, London, United Kingdom.
Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London, London, United Kingdom.
Elife. 2017 Mar 14;6:e22001. doi: 10.7554/eLife.22001.
Cognitive functions such as working memory (WM) are emergent properties of large-scale network interactions. Synchronisation of oscillatory activity might contribute to WM by enabling the coordination of long-range processes. However, causal evidence for the way oscillatory activity shapes network dynamics and behavior in humans is limited. Here we applied transcranial alternating current stimulation (tACS) to exogenously modulate oscillatory activity in a right frontoparietal network that supports WM. Externally induced synchronization improved performance when cognitive demands were high. Simultaneously collected fMRI data reveals tACS effects dependent on the relative phase of the stimulation and the internal cognitive processing state. Specifically, synchronous tACS during the verbal WM task increased parietal activity, which correlated with behavioral performance. Furthermore, functional connectivity results indicate that the relative phase of frontoparietal stimulation influences information flow within the WM network. Overall, our findings demonstrate a link between behavioral performance in a demanding WM task and large-scale brain synchronization.
诸如工作记忆（WM）等认知功能是大规模网络相互作用的涌现特性。振荡活动的同步可能通过协调远程过程来促进工作记忆。然而，关于振荡活动塑造人类网络动态和行为方式的因果证据有限。在这里，我们应用经颅交流电刺激（tACS）来外源性调节支持工作记忆的右侧额顶网络中的振荡活动。当认知需求较高时，外部诱导的同步改善了表现。同时收集的功能磁共振成像数据显示，tACS效应取决于刺激的相对相位和内部认知处理状态。具体而言，言语工作记忆任务期间的同步tACS增加了顶叶活动，这与行为表现相关。此外，功能连接结果表明，额顶叶刺激的相对相位会影响工作记忆网络内的信息流。总体而言，我们的研究结果证明了在要求苛刻的工作记忆任务中的行为表现与大规模脑同步之间的联系。
