Curious Hippocampal Subfields: An Ultra High-Field FMRI Study on Curiosity-Enhanced Memory

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Tamas Foldes¹ (foldes.andrei@gmail.com), Charlotte Murphy², Carl Hodgetts¹, Matthias Gruber¹; ¹Cardiff University, ²Royal Holloway, University of London

Curiosity is a powerful motivator for learning and memory. While states of curiosity affect hippocampus-dependent memory formation via the dopaminergic circuit, it is unknown how different hippocampal subfields contribute to curiosity-related memory enhancements. Consistent with theories and studies in rodents on the role of how the dopaminergic circuit interacts with specific hippocampal subfields in support of memory formation, we addressed the question of how the ventral tegmental area (VTA) and hippocampal subfields support curiosity-related memory enhancements. In combination with 7T fMRI, healthy participants (N=19) encoded trivia questions and answers associated with high or low curiosity. Further, participants also took part in a pre- and post-encoding resting-state fMRI phase. Replicating previous behavioural findings, participants recalled answers and recognized incidental face images more from high- than from low-curiosity conditions. When participants were in a state of high curiosity, Bayesian region-based analysis of univariate BOLD activity revealed moderate evidence for curiosity-related activation (i.e., high vs. low curiosity) in the VTA and subiculum. In addition, we found strong evidence that VTA BOLD activity during the presentation of trivia questions (i.e., during curiosity elicitation) predicted curiosity-related memory enhancements. Comparing pre- and post-encoding resting-state periods, we observed moderate evidence for increased resting-state functional connectivity between the VTA and subiculum during the post- compared to pre-encoding rest periods. These findings suggest the involvement of the VTA and subiculum in curiosity-related memory processes. Furthermore, research on the influence of the dopaminergic circuit on hippocampal subfields in humans may illuminate cross-species commonalities that are pivotal for memory formation.

Topic Area: LONG-TERM MEMORY: Episodic