Top-down attention shifts behavioral and neural event boundaries in narratives with overlapping event scripts

Abstract

SummaryUnderstanding and remembering the complex experiences of everyday life is only possible because we can draw on prior knowledge about how events in our world unfold over time. How does the brain construct event representations using our library of schematic scripts, and what are the behavioral and neural consequences of activating a specific script during perception? We developed a novel set of 16 stories, each of which combines one of four location-relevant event scripts (restaurant, airport, grocery store, lecture hall) with one of four socially-relevant event scripts (breakup, proposal, business deal, meet cute). Participants in an fMRI study and a separate online study listened to these stories after being primed to attend to one of the two scripts or without priming. Responses in angular gyrus, parahippocampal gyrus, and subregions of medial prefrontal cortex (mPFC) were driven by both location and social script information, showing that these regions can track schematic sequences from multiple domains. Comparing priming conditions, we found that activating a location-related event script shifted the timing of subjective event boundaries to align with script-relevant changes in the narratives. This behavioral shift was mirrored by shifts in the timing of neural responses, with mPFC event boundaries (identified using a Hidden Markov Model) aligning to location-relevant rather than socially-relevant boundaries when participants were location primed. Our findings demonstrate that neural event dynamics are actively modulated by top-down goals, and provide new insight into how narrative event representations are constructed through the activation of temporally-structured prior knowledge.