Center for Neural Science, New York University, New York, NY, USA; Neuroscience Institute, NYU Grossman School of Medicine, New York University, New York, NY, USA.
Department of Psychiatry, NYU Grossman School of Medicine, New York University, New York, NY, USA.
Cell Rep. 2024 Sep 24;43(9):114702. doi: 10.1016/j.celrep.2024.114702. Epub 2024 Aug 31.
Representation of the environment by hippocampal populations is known to drift even within a familiar environment, which could reflect gradual changes in single-cell activity or result from averaging across discrete switches of single neurons. Disambiguating these possibilities is crucial, as they each imply distinct mechanisms. Leveraging change point detection and model comparison, we find that CA1 population vectors decorrelate gradually within a session. In contrast, individual neurons exhibit predominantly step-like emergence and disappearance of place fields or sustained changes in within-field firing. The changes are not restricted to particular parts of the maze or trials and do not require apparent behavioral changes. The same place fields emerge, disappear, and reappear across days, suggesting that the hippocampus reuses pre-existing assemblies, rather than forming new fields de novo. Our results suggest an internally driven perpetual step-like reorganization of the neuronal assemblies.
海马体群体对环境的表示已知会在熟悉的环境中漂移，这可能反映了单个细胞活动的逐渐变化，或者是由于离散的单个神经元切换的平均结果。区分这些可能性至关重要，因为它们各自暗示着不同的机制。利用变点检测和模型比较，我们发现 CA1 群体向量在一个会话中逐渐去相关。相比之下，单个神经元主要表现出位置场的阶跃式出现和消失，或者场内放电的持续变化。这些变化不仅限于迷宫或试验的特定部分，也不需要明显的行为变化。相同的位置场在不同的日子里出现、消失和重现，这表明海马体重新使用预先存在的集合，而不是从头开始形成新的场。我们的结果表明，神经元集合存在一种内部驱动的、永久的阶跃式重组。
