Hippocampal Repulsion as a Function of Memory Interference and Subjective Beliefs
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Date
2024-12-19
Authors
Guo, Wanjia
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
Resolving memory interference is critical for performing essential tasks in our daily life. The hippocampus is believed to play a critical role in distinguishing similar memories. This dissertation focused on understanding the mechanisms of hippocampal repulsion, which stands for when the representations of two overlapping memories are actively pushed away to be represented less similarly to each other than non-overlapping memories. The first chapter draws direct connections between repulsion and behavioral expression of memory interference resolution. In particular, we show that the timing when repulsion happens is exactly when memory inference is resolved. The second chapter focuses on why repulsion occurs. It provides evidence that repulsion can occur with distinct internal states, even when external stimuli are identical. The third chapter focuses on how the intensity of repulsion changes with different levels of experience and shows that repulsion is not simply a linear process that accumulates with learning. Instead, it is transient and subsides after memory interference is resolved. Across all 3 chapters, the hippocampus was also segmented into subfields, and we consistently found CA3/DG to be the region that showed the repulsion effect, but not CA1.
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Keywords
brain imaging, episodic memory, hippocampus, human fMRI, memory, memory interference