In an exploratory analysis, we checked whether this music-related reactivation extended beyond the DMN. We found specificity to the DMN and visual areas—but not across the whole brain.

As another control, we computed the relationship between reactivation and subsequent memory for the no-music group. When we did this, there was no significant relationship in the DMN; and the music group showed a stronger reactivation–memory link than the no-music group across DMN ROIs.

Yes—the effect was numerically weaker in some areas (angular gyrus) but numerically stronger in other areas (posterior medial cortex); both regions remained significant when using a parcel-based searchlight.

To tease apart these possibilities, we needed a way of measuring initial encoding strength. Prior studies have found that spatial inter-subject correlation (ISC) predicts subsequent memory; we found this in our study also, validating the use of ISC as a measure of initial encoding strength.

We then split reactivation scores by whether the corresponding scene was later remembered or forgotten.

Main Result: Scenes that were remembered showed significantly higher reactivation in key default mode network (DMN) regions—posterior medial cortex and angular gyrus.

We tracked neural reactivation by comparing activity patterns in the music group (during later music repeats) to patterns in the no-music group (during earlier exposures to the same theme). This gave us a measure of how much non-musical event information was brought back online by the music.

Later on, the same theme plays when Joel and Clementine are out on a lake. Does playing the theme in this scene trigger neural reactivation of the earlier scene, and is the degree of reactivation related to how well participants subsequently remember the earlier scene?

For example, in this scene of the movie, Clementine asks for a Valentine’s Day call and Joel walks away while a musical theme plays…