Fig. 3: Firing fields of grid cells modulated by lever location in darkness.
a, Examples of two grid cells. First column: Firing rate maps during random foraging. Second column: Firing of the neuron plotted as a function of the mouse position on the y axis of the arena (Y-position, 0 representing the center of the arena and −40 marking the edge near the bridge) during search. All search paths (gray lines) are shown next to each other and ranked according to the Y-position of the lever box (black dots) on each trial. Red dots are spikes of the neuron. Third column: similar to the second column, shown for homing. b, Two trial matrices shown for the first grid cell example in a during search. The left trial matrix shows the firing rate as a function of the mouse’s position along the y axis of the arena (Y-position). The right matrix shows the neuron’s firing rate as a function of the distance between the mouse and the lever box. Firing rate as a function of Y-position or lever distance is shown on top of the trial matrix. c, Trial matrix of grid cell firing rate as a function of the mouse position along the y axis of the arena (Y-position, left) and distance between the mouse and the lever box (right) during homing, similar to b. d, Mean trial matrix correlation for all grid cells obtained from trial matrices with y-axis coordinate (top) or distance to the lever box (bottom). Data for search and homing behavior are shown separately (N = 17 mice, two-sided Wilcoxon sign-rank test, Y-position: Search Dark versus Homing Dark: P = 1.526 × 10−5; Lever distance: Search Dark versus Homing Dark: P = 7.629 × 10−5); Data are presented as mean values ± s.e.m. e, Trial matrix of grid cell firing rate as a function of different variables: Distance, Y-position, Lever distance and Time during search (top) and homing (bottom). Data for dark trials are shown (N = 17 mouse, two-sided Wilcoxon sign-rank test with Holm–Bonferroni correction, Search: Distance versus Y-position: P = 1.068 × 10−3, Y-position versus Time: P = 4.639 × 10−3; Homing: Lever distance versus Distance: P = 1.343 × 10−3, Lever distance versus Y-position: P = 1.526 × 10−5); Data are presented as mean values ± s.e.m.
