Amygdala-hippocampal interactions predict temporal memory precision

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Jingyi Wang¹ (jy_wang@ucsb.edu), Joanne Stasiak¹, Scott T. Grafton¹, Regina C. Lapate¹; ¹University of California, Santa Barbara

Our episodic memories are not faithful replicas of the past. Burgeoning behavioral evidence indicates that temporal aspects of episodic memory–such as remembering when an event occurred–are sculpted by emotional states (McClay et al, 2023; Li and Lapate, 2023; Palombo and Cocquyt, 2020; Wang and Lapate, 2023). However, the neural bases of the influence of emotion on temporal memory remain unclear. Functional MRI studies have shown that the similarity of hippocampal multivariate patterns over time reflects the fidelity of temporal memory, with greater similarity linked with less precise temporal memory estimates (Jenkins and Ranganath, 2010; Hsieh et al., 2014; Ezzyat and Davachi, 2014). Given the centrality of amygdala function in emotion, as well as the robust anatomical connections between the amygdala and hippocampus, we examined whether trial-wise amygdala activity during emotional processing modulates the trial-wise similarity of hippocampal patterns. Participants performed a task that manipulated emotional valence and action goals and used trial-unique emotional pictures. After the experiment, participants performed a surprise temporal memory task, in which they were asked to estimate when during the experiment each emotional picture was shown. Replicating previous findings (Jenkins and Ranganath, 2010), higher hippocampal pattern similarity was associated with worse temporal memory–a finding particularly pronounced in the posterior hippocampus. Critically, trial-wise amygdala activation predicted greater hippocampal pattern similarity, an association that was present throughout the longitudinal axis of the hippocampus. Collectively, these results underscore the interconnectedness of amygdala and hippocampal processes, and suggest a mechanism through which amygdala-engaging emotional events may sculpt temporal memory.

Topic Area: LONG-TERM MEMORY: Episodic