Fig. 4: Anticipatory pattern typicality in the hippocampus is uniquely associated with curiosity and subsequent recall.

a For the convergence state analysis, patterns of activation for each trial were extracted from each of the ROIs (Brain icon created with BioRender.com). Convergence states were operationalized as pattern typicality, or the distance between the activation pattern of each trial and an independently defined centroid representing the prototypical state). A leave-one-run-out approach was used where the cluster centroid was identified using data from N-1 runs. This centroid was then used as the origin to quantify the distance for trials from the left-out run. Patterns showing higher typicality, (i.e., shorter distance from the centroid) are considered to exhibit greater convergence than patterns more eccentric from the centroid. b During the anticipation of High-Curiosity (orange) trivia answers, patterns of activation exhibited higher typicality in the hippocampus (HPC, p = 0.011), but not the surrounding medial temporal lobe cortices (PHC: Parahippocampal cortex; PRC: Perirhinal cortex) (N = 23 participants). The larger dots in each panel represents the group mean, while the smaller dots represent the mean distance for each participant. c We used a mixed-effects logistic regression model to predict memory outcome for each trial using the pattern typicality of the medial temporal lobe ROIs (N = 23 participants). Hippocampal typicality was the only significant predictor of subsequent recall (p = 0.008). Bar graph of each panel represents the parameter estimate of each ROI in the full model. For visualization, the estimated change in probability of recall (demeaned within subject) is plotted against the distance from centroid for each ROI. Light gray lines depict the slope for each participant, while the solid black line depicts the mean slope across all participants. Error bars represent the SEM. *p < 0.05, **p < 0.01.