The entorhinal spatial map integrates visual identity information of landmarks

Abstract

The location and identity of landmarks provide spatial and nonspatial information of an environment, respectively, to guide spatial navigation. While the medial entorhinal cortex (MEC) is essential for representing spatial information, it is unclear whether it also encodes landmark identity. Here, we conducted two-photon calcium imaging of the MEC when mice navigated in multiple virtual environments, and discovered a general ability of the MEC to encode landmark identity through cue cells, which responded to individual landmarks during virtual navigation. Cue cells represented landmark identity by exhibiting more distinct activity patterns between visually disparate landmarks than identical ones. The representation was modulated by the spatial shift of cue cell activity relative to landmark location. Moreover, the identity encoding by the same cue cell population changed between different environments but was maintained within the same environment despite increased experience. In contrast, landmark location encoding by cue cells was regulated by experience, suggesting different mechanisms underlying the encodings of landmark identity and location. Finally, compared to cue cells, grid cells weakly encoded landmark identity but more robustly encoded landmark location. Thus, the MEC integrates both spatial and nonspatial information during navigation, but potentially through different circuit mechanisms.