Kwon Dasom, Kim Jungwoo, Yoo Seng Bum Michael, Shim Won Mok
Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, Republic of Korea.
Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Republic of Korea.
Nat Commun. 2025 Jan 14;16(1):641. doi: 10.1038/s41467-025-55833-x.
Our naturalistic experiences are organized into memories through multiple processes, including novelty encoding, memory formation, and retrieval. However, the neural mechanisms coordinating these processes remain elusive. Using fMRI data acquired during movie viewing and subsequent narrative recall, we examine hippocampal neural subspaces associated with distinct memory processes and characterized their relationships. We quantify novelty in character co-occurrences and the valence of relationships and estimate event memorability. Within the hippocampus, the novelty subspaces encoding each type exhibit partial overlap, and these overlapping novelty subspaces align with the subspace involved in memorability. Notably, following event boundaries, hippocampal states within these subspaces align inversely along a shared coding axis, predicting subsequent recall performance. This novelty-memorability alignment is selectively observed during encoding but not during retrieval. Finally, the identified functional subspaces reflect the intrinsic functional organization of the hippocampus. Our findings offer insights into how the hippocampus dynamically coordinates representations underlying memory encoding and retrieval at the population level to transform ongoing experiences into enduring memories.
我们的自然主义体验通过多种过程被组织成记忆，包括新奇编码、记忆形成和检索。然而，协调这些过程的神经机制仍然难以捉摸。利用在观看电影和随后的叙事回忆期间获取的功能磁共振成像（fMRI）数据，我们研究了与不同记忆过程相关的海马神经子空间，并描述了它们之间的关系。我们量化了角色共现中的新奇性以及关系的效价，并估计了事件的可记忆性。在海马体内，编码每种类型的新奇性子空间存在部分重叠，并且这些重叠的新奇性子空间与涉及可记忆性的子空间对齐。值得注意的是，在事件边界之后，这些子空间内的海马状态沿着共享编码轴反向对齐，预测随后的回忆表现。这种新奇性 - 可记忆性对齐在编码期间被选择性地观察到，但在检索期间未被观察到。最后，所确定的功能子空间反映了海马体的内在功能组织。我们的研究结果为海马体如何在群体水平上动态协调记忆编码和检索背后的表征，将正在进行的体验转化为持久记忆提供了见解。
