研究人员使用了一种光遗传操作方法，在大鼠穿越特定空间轨迹时扰乱位置细胞的序列结构，但不扰乱全局网络动力学。这种扰动取消了这些轨迹的重放和预测表征的发展，导致在记忆引导的导航过程中学习新的最佳轨迹的能力受损。然而，位置细胞组装的重新激活和奖赏情境关联学习却不受影响。
这些研究结果表明，两种互补的海马编码之间存在机理上的分离：联想编码（通过协同作用）和预测编码（通过序列）。
据悉，情景记忆包括学习和回忆项目与其时空背景之间的关联。这些记忆可进一步用于生成能够进行预测的内部世界模型。支持记忆的这些联想和预测方面的机制尚不清楚。
附：英文原文
Title: Associative and predictive hippocampal codes support memory-guided behaviors
Author: Can Liu, Ralitsa Todorova, Wenbo Tang, Azahara Oliva, Antonio Fernandez-Ruiz
Issue&Volume: 2023-10-20
Abstract: Episodic memory involves learning and recalling associations between items and their spatiotemporal context. Those memories can be further used to generate internal models of the world that enable predictions to be made. The mechanisms that support these associative and predictive aspects of memory are not yet understood. In this study, we used an optogenetic manipulation to perturb the sequential structure, but not global network dynamics, of place cells as rats traversed specific spatial trajectories. This perturbation abolished replay of those trajectories and the development of predictive representations, leading to impaired learning of new optimal trajectories during memory-guided navigation. However, place cell assembly reactivation and reward-context associative learning were unaffected. Our results show a mechanistic dissociation between two complementary hippocampal codes: an associative code (through coactivity) and a predictive code (through sequences).
DOI: adi8237
Source: https://www.science.org/doi/10.1126/science.adi8237