Memories are dynamic constructs whose properties change with time and experience. The biological mechanisms underpinning these dynamics remain elusive, particularly concerning how shifts in the composition of memory-encoding neuronal ensembles influence the evolution of a memory over time. By targeting developmentally distinct subpopulations of principal neurons, we discovered that memory encoding resulted in the concurrent establishment of multiple memory traces in the mouse hippocampus. Two of these traces were instantiated in subpopulations of early- and late-born neurons and followed distinct reactivation trajectories after encoding. The divergent recruitment of these subpopulations underpinned gradual reorganization of memory ensembles and modulated memory persistence and plasticity across multiple learning episodes. Thus, our findings reveal profound and intricate relationships between ensemble dynamics and the progression of memories over time.

中文翻译：

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发育定义的神经元群的不同募集支持记忆动态


记忆是动态的构造，其属性随着时间和经验而变化。支撑这些动态的生物机制仍然难以捉摸，特别是关于记忆编码神经元群的组成变化如何影响记忆随时间的演变。通过针对主要神经元发育上不同的亚群，我们发现记忆编码导致小鼠海马体中同时建立多个记忆痕迹。其中两条痕迹在早生和晚生神经元的亚群中实例化，并在编码后遵循不同的重新激活轨迹。这些亚群的不同招募支撑了记忆整体的逐渐重组，并调节了多个学习过程中的记忆持久性和可塑性。因此，我们的研究结果揭示了整体动力学与记忆随时间的进展之间深刻而复杂的关系。