PT - JOURNAL ARTICLE AU - Kimberly L. Stachenfeld AU - Matthew M. Botvinick AU - Samuel J. Gershman TI - The hippocampus as a predictive map AID - 10.1101/097170 DP - 2017 Jan 01 TA - bioRxiv PG - 097170 4099 - http://biorxiv.org/content/early/2017/06/07/097170.short 4100 - http://biorxiv.org/content/early/2017/06/07/097170.full AB - A cognitive map has long been the dominant metaphor for hippocampal function, embracing the idea that place cells encode a geometric representation of space. However, evidence for predictive coding, reward sensitivity, and policy dependence in place cells suggests that the representation is not purely spatial. We approach this puzzle from a reinforcement learning perspective: what kind of spatial representation is most useful for maximizing future reward? We show that the answer takes the form of a predictive representation. This representation captures many aspects of place cell responses that fall outside the traditional view of a cognitive map. Furthermore, we argue that entorhinal grid cells encode a low-dimensional basis set for the predictive representation, useful for suppressing noise in predictions and extracting multiscale structure for hierarchical planning.