The hippocampus appears to implement two core but highly distinct functions in the brain: long term memory retrieval and planning and spatial navigation. Naively, these functions appear very different algorithmically. In this short note, we demonstrate that two powerful algorithms that have each independently been proposed to underlie the hippocampal operation for each function -- personalized page-rank for memory retrieval, and successor representations for planning and navigation, are in fact isomorphic and utilize the same underlying representation -- the stationary distribution of a random walk on a graph. We hypothesize that the core computational function of the hippocampus is to compute this representation on arbitrary input graphs.

翻译：海马体在大脑中似乎实现了两个核心但高度不同的功能：长期记忆检索以及规划与空间导航。从表面上看，这些功能在算法层面显得非常不同。在这篇简短的研究笔记中，我们证明了两种强大的算法——个性化PageRank（用于记忆检索）与后继表示（用于规划与导航）——虽然各自独立地被提出作为海马体对应功能的实现基础，但实际上是同构的，并且利用了相同的底层表示：图上随机游走的平稳分布。我们提出假设：海马体的核心计算功能是在任意输入图上计算这一表示。