A high-resolution investigation into the influence of interference on memory: Examining the role of the visual cortex and subregions of the hippocampus

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

Rebecca Wagner¹, Luke Dubec¹, John West¹, Jordan Chamberlain¹, Nancy Dennis¹; ¹The Pennsylvania State University

Episodic memory accuracy is supported by pattern completion and pattern separation processes mediated by neural activity in the occipital cortex and subregions of the hippocampus, including CA1, dentate gyrus (DG), and CA3. These processes can be affected by interference, both from time and increased similarity between the features present in old and new information. The present study utilized high-resolution fMRI during a continuous recognition mnemonic similarity task to explore how increasing interference influences both processes in younger adults. We manipulated interference by systematically increasing the number of trials between when an image was first presented and when it was either re-presented (i.e., targets) or when a perceptually similar lure was presented. Behaviorally, we found that both accurate recognition for targets as well as lure discriminability significantly decreased with increasing interference. Group-level univariate analyses in visual cortices showed that activation differences between targets and lures diminished with increasing interference, such that there were greater differences in the low interference condition compared to the high interference condition. Pattern similarity analyses within subject-specific CA1 and DG/CA3 regions showed a different pattern. Specifically, neural similarity between targets and correctly rejected lures diminished with increasing interference, such that greater pattern overlap was found for the low interference condition. Taken together, results suggest that increasing interference negatively affects the fidelity of young adults’ neural activation, as well as their ability to accurately discriminate previously experienced information from novel, yet similar information.

Topic Area: LONG-TERM MEMORY: Episodic