Fig. 6: Interaction between map-like representations in the hippocampus and individual action representations in SMA.

A Logic of the generalized psycho-physiological interaction (gPPI) analysis. (1) Extracted time-series from a ROI used as a seed region. (2) Onset regressors for each condition, convolved with a hemodynamic response function (HRF) to predict condition-specific activity. The last two regressors constitute the product of (1) and each of the task conditions (2,3), modelling the PPI term (see Methods for details). The two PPI regressors were contrasted between the two conditions to obtain condition-dependent change in the correlation between activity in the seed ROI and each of the other voxels in the brain. B, C In line with the modulation of hippocampal activity during the first Comparison Task based on the distance in the action-outcome space, we expected a modulation in the connectivity between the hippocampus (HPC) and the supplementary motor area (SMA), suggesting a reciprocal communication between motor regions and the hippocampus during the action comparison process. The analysis was repeated twice, once using the HPC and once using the SMA as seed regions and extracting the parameter estimates from the other region. At the group level, the connectivity between these regions increased for trials with long distances compared to those with shorter distances (t(45) = 2.42, p = 0.021, Cohen’s d = 0.35, 95% CI= [−0.241, 0.956]; two-sided t-test). Dots represent data from n  =  46 participants. boxplots show median and upper/lower quartile with whiskers extending to the most extreme data point within 1.5 interquartile ranges above/below the quartiles; black circles with error bars correspond to mean ± SEM; distributions depict probability density functions of data points. Source data are provided as a Source Data file. *p < 0.05.