A Unified Dynamic Model for Learning, Replay, and Sharp-Wave/Ripples
A Unified Dynamic Model for Learning, Replay, and Sharp-Wave/Ripples
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DOI：
10.1523/jneurosci.3977-14.2015
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发表时间：
2015-12-09
影响因子：
5.3
通讯作者：
Memmesheimer, Raoul-Martin
中科院分区：
文献类型：
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作者：
Jahnke, Sven;Timme, Marc;Memmesheimer, Raoul-Martin
海马活动对于情景记忆的形成和巩固至关重要。在休息和睡眠阶段，它表现出尖波/波纹（SPW/R）复合体，这是活动增加的短暂发作，并叠加高频振荡。同时，反映先前行为的尖峰序列（例如空间中的遍历轨迹）会被重播。尽管这些现象被认为对于情景记忆的形成和巩固至关重要，但它们的神经生理机制尚不清楚。在这里，我们提出了一个统一的模型，展示了如何存储经验并随后与 SPW/R 相关联地重放经验。我们认为重放和 SPW/R 是紧密相连的，因为它们相互生成并相互支持。其基本机制是基于非线性树突计算，该计算可归因于在海马区 CA1 和 CA3 中显着发现的树突钠尖峰，其中还生成 SPW/R 和重放。除了为 SPW/R 分配重放和记忆处理的关键作用外，所提出的机制还解释了它们的特征，例如振荡频率和整体波形。研究结果为海马回路学习的动态方面提供了新的线索。
Hippocampal activity is fundamental for episodic memory formation and consolidation. During phases of rest and sleep, it exhibits sharp-wave/ripple (SPW/R) complexes, which are short episodes of increased activity with superimposed high-frequency oscillations. Simultaneously, spike sequences reflecting previous behavior, such as traversed trajectories in space, are replayed. Whereas these phenomena are thought to be crucial for the formation and consolidation of episodic memory, their neurophysiological mechanisms are not well understood. Here we present a unified model showing how experience may be stored and thereafter replayed in association with SPW/Rs. We propose that replay and SPW/Rs are tightly interconnected as they mutually generate and support each other. The underlying mechanism is based on the nonlinear dendritic computation attributable to dendritic sodium spikes that have been prominently found in the hippocampal regions CA1 and CA3, where SPW/Rs and replay are also generated. Besides assigning SPW/Rs a crucial role for replay and thus memory processing, the proposed mechanism also explains their characteristic features, such as the oscillation frequency and the overall wave form. The results shed a new light on the dynamical aspects of hippocampal circuit learning.