芝加哥大学Mark E. J. Sheffield小组近日取得一项新成果。经过不懈努力，他们的最新研究揭示了突触可塑性规则驱动海马体的表征转移。这一研究成果于2025年3月20日发表在国际顶尖学术期刊《自然—神经科学》上。

研究团队认为海马体位置场（PF）在记忆形成和熟悉过程中是一个持续可塑性的指标。通过在脉冲位置细胞的计算模型中实施不同的可塑性规则，并将其与小鼠在熟悉和新环境中导航时实验测量的突触可塑性进行比较，该课题组研究人员发现行为时间尺度突触可塑性（BTSP），而不是Hebbian脉冲时间依赖可塑性（STDP），最好地解释了脉冲位移动力学。触发btsp的事件很少，但在新的体验中更频繁。在探索过程中，它们的概率是动态的——它在PF发作后衰减，但继续推动种群水平的代表性漂移。此外，他们的结果表明，BTSP发生在CA3中，但频率较低，而且在现象上与CA1不同。总的来说，他们的研究为理解突触可塑性如何在学习过程中持续塑造神经元表征提供了一个新的框架。

研究人员表示，突触可塑性被广泛认为支持大脑中的记忆存储，但决定体内有效突触变化的规则尚不清楚。

附：英文原文

Title: Synaptic plasticity rules driving representational shifting in the hippocampus

Author: Madar, Antoine D., Jiang, Anqi, Dong, Can, Sheffield, Mark E. J.

Issue&Volume: 2025-03-20

Abstract: Synaptic plasticity is widely thought to support memory storage in the brain, but the rules determining impactful synaptic changes in vivo are not known. We considered the trial-by-trial shifting dynamics of hippocampal place fields (PF) as an indicator of ongoing plasticity during memory formation and familiarization. By implementing different plasticity rules in computational models of spiking place cells and comparing them to experimentally measured PFs from mice navigating familiar and new environments, we found that behavioral timescale synaptic plasticity (BTSP), rather than Hebbian spike-timing-dependent plasticity (STDP), best explains PF shifting dynamics. BTSP-triggering events are rare, but more frequent during new experiences. During exploration, their probability is dynamic—it decays after PF onset, but continually drives a population-level representational drift. Additionally, our results show that BTSP occurs in CA3 but is less frequent and phenomenologically different than in CA1. Overall, our study provides a new framework to understand how synaptic plasticity continuously shapes neuronal representations during learning.

DOI: 10.1038/s41593-025-01894-6

Source: https://www.nature.com/articles/s41593-025-01894-6