Fig. 4: Spatial representation for multiple environments during early development.

a Three example cells (columns) in 1D and 2D environments at P18. Top, rate maps for two running directions on the track; bottom, rate maps in the box. The spatial information (SI) scores were labeled on top. The shaded region indicates SD. b–d Same as (a), but for example cells at P21, P25, and P28, respectively. e Contour plots showing the distribution of SI scores of the same cells recorded in 1D and 2D environments in developing (top row) and adult (bottom row) rats. The Spearman’s rank correlation coefficients of SI scores between two environments and the respective p values were labeled. f Spearman’s rank correlation coefficients at various ages. Data were presented as observed values ± the 5^th and 95^th percentiles of the bootstrapped distribution. The correlation values decreased with age (Pearson correlation coefficient r = − 0.92, p = 7.45 × 10^–5, n = 11 ages, 9 rats), but not with the recording days in adults (r = 0.21, p = 0.57, n = 10 days, 5 rats). g Schematics of behavioral paradigms illustrating the employment of a set of novel apparatus in a different room after five days of recording. h Comparisons of correlations of SI between 1D and 2D environments under various conditions. Blue: recordings in Environment Set 1 (13 rat pups from P17-21, 9 of which continued for P22-28, and 5 adult rats from Day 1-5). Orange: recordings in Environment Set 2 (4 rat pups from P22-25, which previously exposed to Environment Set 1 from P17-21, and 3 adult rats from Day 6-10). One-sided Permutation tests with Bonferroni correction for the difference of correlation values between groups: P17-20 vs. P22-25 (novel): p < 0.001 for each corresponding day; P17-21 vs. Day 1-5 (adults): p < 0.001 for each corresponding day; P22-25 (familiar) vs. P22-25 (novel): p < 0.001 for P22; p = 0.20 for P23; p = 0.16 for P24, p = 0.054 for P25. Source data are provided as a Source Data file.