Chandra Sarthak, Sharma Sugandha, Chaudhuri Rishidev, Fiete Ila
Department of Brain and Cognitive Sciences and McGovern Institute, MIT, Cambridge, MA, USA.
Center for Neuroscience, Department of Neurobiology, Physiology and Behavior, University of California Davis, Davis, CA, USA.
Nature. 2025 Feb;638(8051):739-751. doi: 10.1038/s41586-024-08392-y. Epub 2025 Jan 15.
Hippocampal circuits in the brain enable two distinct cognitive functions: the construction of spatial maps for navigation, and the storage of sequential episodic memories. Although there have been advances in modelling spatial representations in the hippocampus, we lack good models of its role in episodic memory. Here we present a neocortical-entorhinal-hippocampal network model that implements a high-capacity general associative memory, spatial memory and episodic memory. By factoring content storage from the dynamics of generating error-correcting stable states, the circuit (which we call vector hippocampal scaffolded heteroassociative memory (Vector-HaSH)) avoids the memory cliff of prior memory models, and instead exhibits a graceful trade-off between number of stored items and recall detail. A pre-structured internal scaffold based on grid cell states is essential for constructing even non-spatial episodic memory: it enables high-capacity sequence memorization by abstracting the chaining problem into one of learning low-dimensional transitions. Vector-HaSH reproduces several hippocampal experiments on spatial mapping and context-based representations, and provides a circuit model of the 'memory palaces' used by memory athletes. Thus, this work provides a unified understanding of the spatial mapping and associative and episodic memory roles of the hippocampus.
构建用于导航的空间地图，以及存储连续的情景记忆。尽管在海马体空间表征建模方面已取得进展，但我们仍缺乏关于其在情景记忆中作用的良好模型。在此，我们提出一种新皮质 - 内嗅皮质 - 海马网络模型，该模型实现了高容量的通用联想记忆、空间记忆和情景记忆。通过将内容存储与生成纠错稳定状态的动态过程分离，该回路（我们称之为向量海马支架异联想记忆（Vector - HaSH））避免了先前记忆模型的记忆悬崖，而是在存储项目数量和回忆细节之间展现出一种优雅的权衡。基于网格细胞状态的预结构化内部支架对于构建甚至非空间情景记忆至关重要：它通过将链式问题抽象为学习低维转换问题之一，实现了高容量序列记忆。Vector - HaSH重现了多项关于空间映射和基于上下文表征的海马实验，并提供了记忆运动员所使用“记忆宫殿”的回路模型。因此，这项工作为海马体的空间映射以及联想和情景记忆作用提供了统一的理解。
