Neural codes track prior events in a narrative and predict subsequent memory for details

Throughout our lives, we learn schemas that specify what types of events to expect in certain contexts and the temporal order in which these events typically unfold. Here, our first goal was to investigate how such context-dependent temporal structures are represented in the brain during processing of temporally-extended events. To accomplish this, we ran a 2-day fMRI study in which we exposed participants to many unique animated videos of weddings composed of sequences of rituals; each sequence originated from one of two fictional cultures (North and South), where rituals were shared across cultures, but the transition structure between these rituals differed across cultures. The results, obtained using representational similarity analysis and subsequently confirmed with an unsupervised (K-means) algorithm, revealed that context-dependent temporal structure is represented in multiple ways in parallel, including distinct neural representations for the culture, for particular sequences, and for past and current events within the sequence. Our second goal was to test the hypothesis that neural schema representations scaffold memory for specific details. In keeping with this hypothesis, we found that the strength of the neural representation of the North/South schema for a particular wedding predicted subsequent episodic memory for the details of that wedding.