a, Semi-transparent illustration of the dome apparatus. b, Photo of the apparatus. The dome is raised to allow visualization of the interior, but it is lowered as in (a) for the experiment. c, Illustration of experimental gain G. From the same initial positions of the landmarks and rat, three gain conditions are shown, in both lab (top) and landmark (bottom) frames of reference. In each case, the rat runs 90° in the lab frame. d, Profile of gain change and epochs during a typical session. An annular ring is always projected at the top of the dome (as shown in (a)) for illumination purposes, and is not turned off even in Epoch 4. e, Representative firing rate maps for five different units from five separate gain manipulation sessions, shown in the lab frame (top, middle rows) and landmark frame (bottom row) during Epoch 3 (constant experimental gain). Plots in the top row are color scaled to their own individual maximum firing rates; middle and bottom row plots are color scaled to the maximum firing rate of the bottom plot of each pair.