Entrainment of Prefrontal Beta Oscillations Induces an Endogenous Echo and Impairs Memory Formation
Entrainment of Prefrontal Beta Oscillations Induces an Endogenous Echo and Impairs Memory Formation
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DOI：
10.1016/j.cub.2014.03.007
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发表时间：
2014-04-14
期刊：
影响因子：
9.2
通讯作者：
Fellner, Marie-Christin
中科院分区：
文献类型：
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作者：
Hanslmayr, Simon;Matuschek, Jonas;Fellner, Marie-Christin
所有频带的脑振荡在记忆形成中起着关键作用[1-4]。具体来说，左侧下前额叶皮层（PFC）的局部神经元组装在β频率（类似于18 Hz）上的去同步已被证明是语言记忆编码的核心[5-8]。然而，前额叶β去同步是否与记忆形成有因果关系，以及这些内源性β振荡是否可以被外部刺激所携带，这些仍然是难以捉摸的。通过联合EEGTMS（经颅磁刺激），我们在这里解决了这些基本问题在人类参与者执行单词列表学习任务。证实了我们的预测，与其他频率（6.8 Hz和10.7 Hz）和无效的假刺激（18.7 Hz）相比，在β (18.7 Hz)下驱动左额下回（IFG）时，记忆编码选择性受损。此外，仅在β刺激后，在左侧IFG中观察到持续振荡的“回声”，其持续时间比刺激期长约1.5 s。这种回声的强度与受试者之间的记忆障碍有关。这些结果表明，在刺激左IFG的β频率中，内源性振荡携带效应和选择性行为损害，表明前额叶β去同步与记忆形成之间存在密切的因果关系。
Brain oscillations across all frequency bands play a key role for memory formation [1-4]. Specifically, desynchronization of local neuronal assemblies in the left inferior prefrontal cortex (PFC) in the beta frequency ( similar to 18 Hz) has been shown to be central for encoding of verbal memories [5-8]. However, it remains elusive whether prefrontal beta desynchronization is causally relevant for memory formation and whether these endogenous beta oscillations can be entrained by external stimulation. By using combined EEGTMS (transcranial magnetic stimulation), we here address these fundamental questions in human participants performing a word-list learning task. Confirming our predictions, memory encoding was selectively impaired when the left inferior frontal gyrus (IFG) was driven at beta (18.7 Hz) compared to stimulation at other frequencies (6.8 Hz and 10.7 Hz) and to ineffective sham stimulation (18.7 Hz). Furthermore, a sustained oscillatory "echo'' in the left IFG, which outlasted the stimulation period by approximately 1.5 s, was observed solely after beta stimulation. The strength of this beta echo was related to memory impairment on a between-subjects level. These results show endogenous oscillatory entrainment effects and behavioral impairment selectively in beta frequency for stimulation of the left IFG, demonstrating an intimate causal relationship between prefrontal beta desynchronization and memory formation.