Extended Data Fig. 8: Stimulus familiarity.
From: Human hippocampal and entorhinal neurons encode the temporal structure of experience
(a) The mean number of outer-inner or inner-outer (I-O) transitions did not differ significantly from the mean number of inner-inner (I-I) transitions (P values from the Wilcoxon signed-rank tests; two-sided; FDR-corrected). (b) Images from the inner nodes were displayed more frequently during exposure phases than images from the outer nodes (P values from the Wilcoxon signed-rank tests; two-sided; FDR-corrected; exact P values equal to 5.88 × 10−5 for all comparisons). (c) Hippocampal-entorhinal neurons did not respond significantly differently to images from the inner versus outer nodes (Wilcoxon signed-rank tests; two-sided; FDR-corrected). Bayes factors supported the null hypotheses (BF01) and are provided in the brackets (paired t-tests; two-sided; Cauchy prior; 0.7071). (d) Relational neurons responded more strongly to directly linked stimuli, regardless of whether their preferred stimulus was at an inner or an outer node (see Extended Data Fig. 4; Wilcoxon signed-rank tests against PRE; two-sided; FDR-corrected). (e) These neurons gradually diminished their selectivity, regardless of whether their preferred stimulus was at an inner or an outer node (see Extended Data Fig. 4; Wilcoxon signed-rank tests against PRE; two-sided; FDR-corrected; exact P values for ‘outer’ (from the bottom to the top): P = 0.004; P = 0.016; P = 2.74 × 10−5; P = 1.73 × 10−5; exact P values for ‘inner’(from the bottom to the top): P = 0.00014; P = 6.56 × 10−5; P = 9.43 × 10−5; P = 5.65 × 10−5). There were no significant differences between the slopes of diminishing selectivity for relational neurons preferring the inner versus outer nodes (outer versus inner; PRE: P = 0.566; E1&2: P = 0.637; E3&4: P = 0.514; E5&6: P = 0.831; POST: P = 0.86; Wilcoxon signed-rank tests, two-sided). (f) We replicated our decoding results (see Fig. 3c) regardless of whether the ‘actual’ image was at an inner or an outer node. Plots show data from all hippocampal-entorhinal neurons (n = 546). P values from Kolmogorov-Smirnov tests between CDFs of respective posterior probabilities (PRE versus subsequent study phases; one-sided). Please note that data used for training (PRE) contained the same number of repetitions of each image. Exact P values for ‘outer-actual’ E3&4: P = 1.56 × 10−8; E5&6: P = 4.82 × 10−8; POST: P = 4.82 × 10−13. Exact P-value for ‘outer-direct’ POST: P = 6.08 × 10−6. Exact P values for ‘inner-actual’ E5&6: P = 2.72 × 10−6; POST: P = 1.58 × 10−4. (g) We also analysed responses of relational neurons when direct and indirect stimuli were repeated a similar number of times (i.e., direct-inner versus indirect-inner; direct-outer versus indirect-outer; all possible combinations). We found the same pattern of results as before (P values from Wilcoxon signed-rank tests against PRE; one-sided). The plot shows the mean ‘direct minus indirect’ difference ( ±s.e.m.) in the 0.1 to 1 s time window (peak-normalized and baseline-corrected). For the definition of box plots, please see the legend of Extended Data Fig. 1.
