Medial Pre-frontal & Hippocampal Functional Connectivity at Encoding Supports Prior Knowledge Leveraged Acquisition Of Novel Events In Older Adults

Poster Session C - Sunday, March 30, 2025, 5:00 – 7:00 pm EDT, Back Bay Ballroom/Republic Ballroom

Rujuta Pradhan¹ (rujuta.p5@gmail.com), Morgan Brucks², Kristen McGatlin¹, James Bartolloti², Alexia Bouslog¹, Dr. Laura Martin², Dr. Heather Bailey¹; ¹Kansas State University, ²University of Kansas Medical Center

Research has shown better episodic memory retention in younger adults (YAs) as compared to older adults (YAs). But studies also show that OAs can leverage their prior knowledge (event schemas, scripts) to facilitate the encoding of newer episodic memories. Neuroimaging studies conducted on YAs report effective connectivity between the medial prefrontal cortex (mPFC) and hippocampus (HPC) at encoding supports retention of new events with stronger schemas/prior knowledge. The current study investigated if the same neural mechanism also underlie older adult’s ability to compensate for deficit in encoding episodic memories. To investigate this, participants in the current study encoded a 30 min video of BBC’s Sherlock in an fMRI scanner and completed free and cued recall tasks following the scan. Behavioral analysis found no difference in the number of events remembered (mean accuracy = 30%) across age groups (n: OA = 36, YA = 38). But mixed effects logistic regression analysis of the imaging data showed greater effective connectivity (Fisher z-transformed Pearson correlation) between mPFC and HPC at event boundaries was predictive of successful recall of events in OAs but not in YAs. Instead, YAs showed a negative correlation between recall success and effective connectivity (β = -0.66, SE = 0.34, z = -1.95, p <0.05). Results confirmed that OA’s event encoding is aided by prior knowledge which was facilitated by greater mPFC-HPC connectivity. Differential processes aiding encoding at event boundaries between OAs and YAs is discussed as a possibility for observing the inverse relationship between connectivity and memory for YAs.

Topic Area: LONG-TERM MEMORY: Episodic