Dissociable neural mechanisms for encoding of memories associated with conceptual and visual-perceptual detail

Poster Session C - Sunday, April 14, 2024, 5:00 – 7:00 pm EDT, Sheraton Hall ABC

Charles Ferris¹ (charlessferris@gmail.com), Rebecca Scheurich¹, Wenbo Yi¹, Caroline Palmer¹, Signy Sheldon¹; ¹McGill University

Encoding everyday events involves processing an array of details, including those pertaining to the unfolding of the event (central details) and those that describe peripheral elements to enrich the encoded memory. Importantly, these peripheral elements can vary, presenting conceptual or perceptual details that further describe the event. Recent theories suggest that there are functionally specialized hippocampal networks along the longitudinal axis (anterior, posterior) for encoding conceptual versus perceptual details. Whether these networks are also activated during encoding of complex events that emphasize these content elements remains unknown. To address this knowledge gap, we conducted a neuroimaging study in which healthy participants (N = 37) listened to three narratives containing different information depending on narrative version. Each narrative began with an introduction detail and contained 14 central details that depicted the unfolding of the presented story and were the same within story type across conditions. Interspersed between the central details were 3 conceptual, visual, or auditory peripheral details (which varied by condition). To test how these peripheral details altered memory encoding while keeping central story details constant, we analyzed neural activity for each narrative condition during the encoding of the 14 central details. Consistent with predictions, we observed enhanced activation in the anterior hippocampus, lateral orbitofrontal cortex, and ventral striatum during encoding of narratives presented with conceptual details. Conversely, we observed enhanced activity in the posterior hippocampus, precuneus, and inferior parietal lobule during encoding of narratives with visual-perceptual details. These results extend theories of hippocampal functional specialization to encoding complex memories.

Topic Area: LONG-TERM MEMORY: Episodic