Threat-Related Long-Term Memory Reinstatement in Hippocampus

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Mrs Busra Tanriverdi¹ (busra.tanriverdi@temple.edu), David Gregory², Ingrid R. Olson³, Jason Chein⁴, Vishnu P. Murty⁵; ¹Temple University

Hippocampus, a brain region that is crucial for memory consolidation, is influenced by threat and arousal in complex ways, and thus is implicated in psychiatric conditions like PTSD. Yet, our understanding of how threat-related representations are reinstated in hippocampus over time remains limited. In a recently collected dataset (N = 47), we test how threat-related information is reinstated in hippocampus 1-week after encoding. On Day-1 (encoding), participants watched six (3 aversive, 3 neutral) short (2-min) movie clips in the scanner and provided arousal ratings after each clip. Twenty-four hours later (Day-2), participants came back to the lab to complete a temporal order memory test. Finally, 1-week after encoding (Day-8), they came back to the scanner and watched a disrupted version of each clip. During the disrupted clips, the screen alternated between the original video (On period: 10 second) and a black screen (Off period: 20 second), while audio remained on for the entire clip. Our planned analyses for this poster will focus on hippocampal memory reinstatement during the disrupted movie watching on Day-8. To test this, we will calculate pattern similarity between the on- and off-periods on Day-8 with the corresponding time frames on Day-1. We hypothesize that there will be higher hippocampal similarity during the off- than on- periods (Off>On), reflecting memory reinstatement. We further expect that this Off>On difference will be higher for the aversive than neutral clips, reflecting threat-related bias in memory reinstatement. Furthermore, we expect that arousal ratings for the clips will amplify these effects.

Topic Area: LONG-TERM MEMORY: Episodic