Abstract
To decide upon relevant behavior, individuals rely on dynamic neural representations of their world, computed from current and past experiences. Many behaviors are goal-directed and thus require some goal representation in the brain. The hippocampal region contains an extended network of specialized cell types coding for defined spatial features that together allow the computation and updating of spatial representations (or cognitive map: Nobel prize 2014 John O’Keefe, Edvard and May-Britt Moser). Among those cells supporting a spatial code, grid cells with their rigid hexagonal firing fields are thought to provide an invariant metric to the hippocampal cognitive map. Yet, environmental geometrical features have been recently shown to distort the grid structure. Given that the hippocampal role goes beyond space, we tested the influence of non-spatial information on the grid organization. We trained rats to daily learn three new reward locations on the cheeseboard maze, while recording from the medial entorhinal cortex and the hippocampal CA1 region. Many grid fields moved towards goal location, leading to long-lasting deformations of the entorhinal map. Therefore, distortions in the grid structure contributes to goal representation during both learning and recall, which demonstrates that grid cells participate in mnemonic coding, beyond providing a simple metric of space.