霍华德休斯医学院Jeffrey C. Magee研究小组近日取得一项新成果。经过不懈努力，他们揭示了海马体中扩展记忆表征的形成。相关论文于2025年6月4日发表在《自然—神经科学》杂志上。

为了验证这一点，课题组研究人员在小鼠学习一项任务的7天半时间里追踪了相同数量的海马CA1位置细胞（PCs）。该团队发现了记忆形成的证据，因为保持稳定位置场的PCs数量和单个PCs的稳定性在一周内逐渐增加，直到大部分表征由长期稳定的PCs组成。稳定的PCs不成比例地代表了与任务相关的学习信息，在行为会话中更早地检索到，并与行为表现表现出很强的相关性。PCs的初始形成和随后几天的恢复都伴随着明显的行为时间尺度突触可塑性（BTSP）迹象，这表明即使是稳定的PCs也会在每次会话中被突触可塑性重新形成。由级联型状态模型支持的进一步实验证据表明，CA1 PCs在活跃的每一天都会增加它们的稳定性，最终形成一个高度稳定的种群。结果表明，CA1记忆是通过增加新的神经元特异性突触可塑性的可能性来实现的，而不是广泛的长期突触重量稳定。

研究人员表示，由不稳定的突触连接的大脑网络是如何存储新信息而不会灾难性地覆盖之前的记忆的，人们对这一点仍然知之甚少。

Title: Formation of an expanding memory representation in the hippocampus

Author: Vaidya, Sachin P., Li, Guanchun, Chitwood, Raymond A., Li, Yiding, Magee, Jeffrey C.

Issue&Volume: 2025-06-04

Abstract: How brain networks connected by labile synapses store new information without catastrophically overwriting previous memories remains poorly understood. To examine this, we tracked the same population of hippocampal CA1 place cells (PCs) as mice learned a task for 7days. We found evidence of memory formation as both the number of PCs maintaining a stable place field and the stability of individual PCs progressively increased across the week until most of the representation was composed of long-term stable PCs. The stable PCs disproportionately represented task-related learned information, were retrieved earlier within a behavioral session and showed a strong correlation with behavioral performance. Both the initial formation of PCs and their retrieval on subsequent days were accompanied by prominent signs of behavioral timescale synaptic plasticity (BTSP), suggesting that even stable PCs were re-formed by synaptic plasticity each session. Further experimental evidence supported by a cascade-type state model indicates that CA1 PCs increase their stability each day they are active, eventually forming a highly stable population. The results suggest that CA1 memory is implemented by an increase in the likelihood of new neuron-specific synaptic plasticity, as opposed to extensive long-term synaptic weight stabilization.

DOI: 10.1038/s41593-025-01986-3

Source: https://www.nature.com/articles/s41593-025-01986-3