Extended Data Fig. 4: Summary of dataset.

Each row indicates 1 of the 72 sessions comprising the dataset during the period in which the landmarks were on. In the left plot, the x axis is laps in the laboratory frame. In the right plot, the x axis is the experimental gain, G. The sessions are chronologically ordered (bottom to top). Sessions from different rats are separated by dashed lines. In all rats, we typically performed smaller manipulations in G first, as initial landmark failure tended to occur at larger manipulations of G. Once landmark control failed, it tended to fail more frequently. The colour represents the ratio between hippocampal and experimental gains (H/G, colour bar, right). Green (H/G = 1) indicates landmark control. Four of the rats (576, 637, 638 and 692) experienced landmark failure (red portions of sessions). Failures happened only when G was less than one (that is, the landmarks moved in the same direction as the rat), and generally occurred at low values of G (less than 0.5) and after rats had experienced several gain-manipulation sessions over days. The asymmetry in landmark control between G < 1 and G > 1 is similar to a study of medial entorhinal cortex⁴⁰. In that study, mice ran on a virtual-reality linear track controlled by a stationary treadmill, and the gain factor was manipulated between the distance travelled on the treadmill versus the virtual-reality track. Grid cells showed asymmetric responses to increases compared with decreases of the gain. Gain increases (G > 1) caused phase shifts in the spatial firing patterns, but gain decreases (G < 1) caused changes in the spatial scales. These results were explained by a model of how grid cells respond to conflicts between self-motion and landmark cues. Although the study did not address the issues of path-integration gain recalibration, as in our current work, its results may provide a causal explanation for the asymmetric responses of place cells to the landmark manipulations seen in the present study.