Rhythmic Working Memory Activation in the Human Hippocampus
Rhythmic Working Memory Activation in the Human Hippocampus
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DOI：
10.1016/j.celrep.2015.09.081
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发表时间：
2015-11-10
期刊：
影响因子：
8.8
通讯作者：
Axmacher, Nikolai
中科院分区：
文献类型：
--
作者：
Leszczynski, Marcin;Fell, Juergen;Axmacher, Nikolai
工作记忆（WM）的维护被认为是依赖于一个单一的持续过程在整个维护期间。这一假设虽然基本，但从未得到验证。我们在两个独立的实验中使用人类海马的颅内脑电图（EEG）记录来研究WM维持的神经动力学。我们观察到两种不同的振荡制度之间的周期性波动：“记忆激活”的周期反映了负载依赖的α功率降低和较低水平的交叉频率耦合（CFC）。它们发生交错的时期，其特征在于独立于负载的高水平的α功率和CFC。在记忆激活期间，一个相关的CFC参数（负载依赖的变化的峰值调制频率）与个人WM能力。这两个时期之间的波动预测成功的表现，并锁定到内源性三角洲振荡的阶段。这些结果表明，海马的维护是一个动态的，而不是恒定的过程，并严重依赖于振荡的层次。
Working memory (WM) maintenance is assumed to rely on a single sustained process throughout the entire maintenance period. This assumption, although fundamental, has never been tested. We used intracranial electroencephalography (EEG) recordings from the human hippocampus in two independent experiments to investigate the neural dynamics underlying WM maintenance. We observed periodic fluctuations between two different oscillatory regimes: Periods of "memory activation'' were reflected by load-dependent alpha power reductions and lower levels of cross-frequency coupling (CFC). They occurred interleaved with periods characterized by load-independent high levels of alpha power and CFC. During memory activation periods, a relevant CFC parameter (load-dependent changes of the peak modulated frequency) correlated with individual WM capacity. Fluctuations between these two periods predicted successful performance and were locked to the phase of endogenous delta oscillations. These results show that hippocampal maintenance is a dynamic rather than constant process and depends critically on a hierarchy of oscillations.