Natural language processing captures memory content associated with shared neural patterns at encoding

Abstract

People can experience the same event yet form distinct memories shaped by individual interpretations. Prior research shows that multivariate activity patterns in the Default Mode Network (DMN) are correlated across individuals during shared experiences, suggesting a role in representing high-level event features. However, it remains unclear whether these shared neural patterns reflect similarity in subsequent memory content. Here, we examined whether memory similarity correlates with intersubject spatial patterns in the DMN. Using topic modeling, we transformed verbal recall into vectors of latent topics to quantify memory similarity across participants. Twenty-four individuals watched and recounted two cartoon movies during fMRI scanning. We found that greater similarity in recalled content was associated with stronger shared activation patterns at encoding, particularly in the posterior medial cortex. These findings highlight the utility of natural language processing tools in linking memory representations to brain activity and underscore the DMNs role in encoding and interpreting complex event features.