Related to Fig. 2. a, Cumulative distribution of mean calcium activity, based on the area under the calcium curve, for all GCs (red), CA2/3 PYRs (blue) and CA1 PYRs (black) recorded in the familiar context. b, As in a, but for the calcium transient rate. c, Cumulative distribution of place field widths for all day 1 familiar-context place cells in the respective hippocampal areas. d, Experimental schematic: place field consistency was measured as the correlation of the average activity on the first and second blocks of five runs in the same context (familiar: F–F′ or novel: N–N′). Place field discrimination was assessed as the correlation of activity maps for different contexts (F–N). e, Activity over distance for cells with a place field on the novel track. Cells were sorted according to their peak activity in novel-track runs and are plotted separately for the first (left) and second (middle) blocks of runs on the novel track and for all runs on the familiar track (right). For the same plots with familiar-context place cells, see Fig. 2c. f, Number of cells with significant place fields (see Methods) in each experiment. Thin lines denote individual experiments (DG, n = 12; CA2/3, n = 7; CA1, n = 15 experiments), thick lines with error bars show mean ± s.e.m. (one-way repeated measures ANOVA). g, Median activity-map correlations between the familiar and novel contexts for experiments with at least 20 place cells on day 1 (circles; DG, n = 6; CA2/3, n = 4; CA1, n = 11 experiments) and their mean ± s.e.m. (ANOVA, Holm–Sidak). h, Pearson’s correlation of place-related activity for cells that had a place field in the familiar context (left) or novel context (right) on day 1. Left box of each pair shows correlation of activity maps for trial blocks on the same track (‘consistency’) and right bar shows correlations with trials on the other track (‘discrimination’) in the same session. Correlations within the same context were always significantly higher than between contexts, except for GCs that had newly acquired a place field on the novel track. i, Trial-to-trial reliability of place cell responses. Place-related firing was more reliable in the familiar than in the novel context and higher in GCs than in PYRs in the familiar context. Differences between areas were not significant for the novel context. j, Each figure shows the run-by-run calcium activity (colour coded) over distance from one individual place cell for one session in the familiar context. Rows denote individual runs. h, i, Boxes, 25th to 75th percentiles; white bars, median; whiskers, 99% range. a–c, h, i, One-way ANOVA on ranks, Dunn’s test. *P < 0.05, **P < 0.01, ***P < 0.001; n.s., not significant. For exact P values see Supplementary Table 1.