Fig. 4: Firing fields of the search and homing paths modulated by the distance to the lever box.
a Example of two pyramidal cells firing during the search behavior of light trials. The neuron on the left fired as a function of position, while the neuron on the right fired as a function of the distance to the lever box. 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. The blue line is the regression line of the spikes (red dots) shown in the plot. b Example of pyramidal cells active during the Search-Light, Search-Dark, Homing-Light, and Homing-Dark conditions. Two different neurons are shown in each condition, one neuron per row. The first row in each condition shows a neuron firing at a set position (typical place cell, labeled as Place field). The second row in the Search-Light, Homing-Light, and Homing-Dark conditions are neurons that fired at a fixed distance from the lever (labeled as Lever distance field). For each neuron, the 2D firing rate map and two trial matrices are shown. The number above the 2D firing rate map is the peak firing rate in the map. The first trial matrix shows the firing rate as a function of the mouse’s position on the y-axis (y-axis in the 2D firing map, 0 being the center of the arena and -40 the edge of the arena near the bridge). The second trial matrix shows the firing rate of the neuron as a function of the distance between the mouse and the lever box. The r value on each matrix is the trial matrix correlation. c Mean trial matrix correlation for active pyramidal cells obtained from trial matrices with y-axis coordinate (left) or distance to the lever box (right). The data are shown separately for light and dark trials and search and homing behavior (n = 9 mice, two-sided Wilcoxon signed-rank test with Bonferroni correction and α set to 0.0125, Y-coordinate, Search-Light vs Search-Dark: P = 1; Y-coordinate, Homing-Light vs Homing-Dark: P = 3.9 × 10-3; Y-coordinate, Search-Dark vs Homing-Dark: P = 3.9 × 10-3; Lever distance, Search-Light vs Search-Dark: P = 3.9 × 10-3; Lever distance, Homing-Light vs Homing-Dark: P = 0.07; Lever distance, Search-Dark vs Homing-Dark: P = 3.9 × 10-3); Data are presented as means +/- SEM. d Information score of 1D firing rate histograms with the firing rate as a function of y-axis coordinate (left) or distance to the lever box (right) (n = 9 mice, two-sided Wilcoxon signed-rank test with Bonferroni correction and α set to 0.0125, Y-coordinate, Search-Light vs Search-Dark: P = 2.7 × 10-2; Y-coordinate, Homing-Light vs Homing-Dark: P = 0.12; Y-coordinate, Search-Dark vs Homing-Dark: P = 7.8 × 10-3; Lever distance, Search-Light vs Search-Dark: P = 3.9 × 10-3; Lever distance, Homing-Light vs Homing-Dark: P = 0.65; Lever distance, Search-Dark vs Homing-Dark: P = 3.9 × 10-3); Data are presented as means +/- SEM. e Example of a neuron with a firing field influenced by the distance to the lever during the homing paths of dark trials. i and ii: Trial matrix of the neuron as a function of the y-axis coordinate and the distance to the lever box, respectively. iii: Y-axis location of the peak firing rate of the neuron and the y-axis location of the lever for single homing paths in darkness. The location of the peak firing rate of the neuron can be predicted by the lever box location. iv: Distribution of r values between firing rate peak location and lever location obtained after shuffling the firing rate values within each trial. The observed r value felt outside the random distribution, indicating a significant correlation between peak rate location and lever location. f Percentage of active pyramidal cells for which the location of their peak firing rate was significantly correlated with the lever position (Chi-square test, Search-Light Vs. Search-Dark: P = 1.1 × 10-2; Homing-Light Vs. Homing-Dark: P = 0.94; Search-Dark Vs. Homing-Dark: P = 1.69 × 10-3). ****P < 0.0001, ns: P > 0.0125. Source data are provided as a Source Data file.
