2023,
Nature Communications.
DOI:
10.1038/s41467-023-44011-6
Theta mediated dynamics of human hippocampal-neocortical learning systems in memory formation and retrieval
Sandra Gattas, Myra Sarai Larson, Lilit Mnatsakanyan, Indranil Sen-Gupta, Sumeet Vadera, A. Lee Swindlehurst, Paul E. Rapp, Jack J. Lin, Michael A. Yassa
Abstract:
Abstract Episodic memory arises as a function of dynamic interactions between the hippocampus and the neocortex, yet the mechanisms have remained elusive. Here, using human intracranial recordings during a mnemonic discrimination task, we report that 4-5 Hz (theta) power is differentially recruited during discrimination vs. overgeneralization, and its phase supports hippocampal-neocortical when memories are being formed and correctly retrieved. Interactions were largely bidirectional, with small but significant net directional biases; a hippocampus-to-neocortex bias during acquisition of new information that was subsequently correctly discriminated, and a neocortex-to-hippocampus bias during accurate discrimination of new stimuli from similar previously learned stimuli. The 4-5 Hz rhythm may facilitate the initial stages of information acquisition by neocortex during learning and the recall of stored information from cortex during retrieval. Future work should further probe these dynamics across different types of tasks and stimuli and computational models may need to be expanded accordingly to accommodate these findings.
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2023-12-31 13:31:00
#paper Theta mediated dynamics ofhuman hippocampal-neocortical learning systems in memory formation and retrieval https://doi.org/10.1038/s41467-023-44011-6 本研究探讨了人类海马-皮层学习系统在记忆编码和提取过程中的θ节律动力学。研究结果表明，θ节律在记忆形成和检索过程中起着重要的调节作用，并且海马和新皮质之间存在信息传递的动态变化。这些发现对于理解记忆的神经机制和相关疾病具有重要意义。具体而言，文章关心三个研究问题：1）在记忆编码和检索过程中，海马和新皮质之间的信息传递方向是如何的？2）在不同条件下，海马和新皮质之间的信息传递是否存在差异？3）Theta频率范围内的神经振荡是否在海马-新皮质学习系统中发挥重要作用？作者记录了8个颅内病人数据，通过模式分离任务（让被试判断old，lure，new）中的电生理信号来揭示4-5hz的θ节律分别在编码和提取过程的作用，以及这一节律如何贡献于海马和皮层的信息交互。结果发现，4-5hz的θ节律在模式完成和模式分离中表现不同，海马和新皮质无论在模式完成还是模式分离还是编码提取阶段都表现出双向信息交流。但这几种条件下存在一定的偏向性，如模式分离（即能够区分相似的项目）4 - 5hz介导了新皮层→海马方向偏差，而如果4-5hz可以在编码阶段介导海马→新皮层方向偏差，那么被试在提取阶段可以更好的识别学过的项目。总体来说海马和新皮层的交互在记忆编码提取以及模式分离和模式整合等不同阶段和条件下展现出了非常动态性的过程，4-5hz的θ震荡在其中起到一定的作用。