Extended Data Fig. 4. Hexagonal modulation for inferred trajectories only for the novel pairs when presented for the first-time.

a. Among all the 88 (83) pairs (F0-F1 and F0-F2) presented during the partner selection task, those pairs that were not presented during behavioral training (always in the absence of feedback) but presented during fMRI for the first time are shown: 83 pairs in white were presented for the first-time for 4 participants; 88 pairs in white and gray were shown for the first-time for 17 participants. The grid effects were tested only for those pairs presented for the first time during the day1 scan. We extracted the mean activity and GP effects for each bin, restricted to when each pair was presented for the first time to participants. b and c. Associated with Figure 4b and c. The mean EC (left panel) and mPFC (middle panel) activity in 30° bins aligned to the EC grid orientation estimated from different blocks acquired in the same day’s scan (b) and the EC grid orientation acquired from a different day’s (day 2) scan (c) with six-fold symmetry. Right panel shows formal comparison of trajectories aligned and misaligned with both methods of computing the EC grid orientation. We found greater activity for the aligned pairs compared to the misaligned pairs to the EC grid orientation in EC and mPFC ROIs (one-sample t-test). d. Associated with Figure 5b. The GP effects in mPFC and bilateral TPJ are modulated by the grid alignment of the inferred trajectories aligned with the EC grid orientation. The GP effects are greater for the aligned pairs compared to misaligned pairs, even when they were presented for the first time (one-sample t-test). Box, lower and upper quartiles; line, median; whiskers, range of the data excluding outliers; +, the whisker’s range of outliers. **, p<0.01; *, p<0.05.