美国斯坦福大学Jordan S. Farrell团队近期取得重要工作进展，他们研究发现了海马齿状突起期间的神经和行为状态转换。相关研究成果2024年3月13日在线发表于《自然》杂志上。

据介绍，不同的大脑和行为状态与有组织的神经群体动力学有关，这些动力学被认为具有特定的认知功能。例如，当小鼠处于“离线”行为状态时，记忆重放事件发生在海马体中被称为尖波涟漪的同步群体事件中，从而实现记忆巩固和计划等认知机制。但是，在这种行为状态下，大脑是如何与外部世界重新接触，并允许获取当前的感官信息或促进新的记忆形成的呢？

研究人员发现，海马体齿状突起可能是这样一种机制的基础，这是一种未被充分研究的群体活动，经常发生在尖波涟漪之间。研究人员发现，齿状突起与明显升高的全脑放电率有关，主要在高阶网络中观察到，并与短暂的觉醒期有关。在齿状突起期间的海马位置编码与小鼠当前的空间位置对齐，不同于伴随着尖波涟漪的记忆回放。

此外，抑制齿状突起的神经活动会破坏联想记忆的形成。因此，齿状突起代表了一种独特的大脑状态，并在非运动行为期间支持记忆，将认知过程的范围扩展到经典的离线功能之外。

附：英文原文

Title: Neural and behavioural state switching during hippocampal dentate spikes

Author: Farrell, Jordan S., Hwaun, Ernie, Dudok, Barna, Soltesz, Ivan

Issue&Volume: 2024-03-13

Abstract: Distinct brain and behavioural states are associated with organized neural population dynamics that are thought to serve specific cognitive functions1,2,3. Memory replay events, for example, occur during synchronous population events called sharp-wave ripples in the hippocampus while mice are in an ‘offline’ behavioural state, enabling cognitive mechanisms such as memory consolidation and planning4,5,6,7,8,9,10,11. But how does the brain re-engage with the external world during this behavioural state and permit access to current sensory information or promote new memory formation Here we found that the hippocampal dentate spike, an understudied population event that frequently occurs between sharp-wave ripples12, may underlie such a mechanism. We show that dentate spikes are associated with distinctly elevated brain-wide firing rates, primarily observed in higher order networks, and couple to brief periods of arousal. Hippocampal place coding during dentate spikes aligns to the mouse’s current spatial location, unlike the memory replay accompanying sharp-wave ripples. Furthermore, inhibiting neural activity during dentate spikes disrupts associative memory formation. Thus, dentate spikes represent a distinct brain state and support memory during non-locomotor behaviour, extending the repertoire of cognitive processes beyond the classical offline functions.

DOI: 10.1038/s41586-024-07192-8

Source: https://www.nature.com/articles/s41586-024-07192-8