2025-07-15 カリフォルニア大学ロサンゼルス校(UCLA)
<関連情報>
- https://newsroom.ucla.edu/releases/brain-region-where-memories-form-research
- https://www.cell.com/neuron/abstract/S0896-6273(25)00360-5
ロクサス・コエレウス(青斑核)の活性化は、海馬の出来事表象を「リセット」し、隣接する記憶を分離する Locus coeruleus activation “resets” hippocampal event representations and separates adjacent memories
David Clewett ∙ Ringo Huang ∙ Lila Davachi
Neuron Published:June 6, 2025
DOI:https://doi.org/10.1016/j.neuron.2025.05.013
Highlights
- Context shifts, or boundaries, promote perception and memory of distinct events
- Arousal and locus coeruleus activity at boundaries predict later memory separation
- Boundary-evoked LC activation enhances pattern separation in dentate gyrus
- Markers of chronically elevated LC output relate to disruptions in event perception
Summary
Memories reflect the ebb and flow of experiences, capturing distinct events from our lives. Using a combination of functional magnetic resonance imaging (fMRI), neuromelanin imaging, and pupillometry, we show that arousal and locus coeruleus (LC) activation segment continuous experiences into discrete memories. As sequences unfold, encountering a context shift or event boundary triggers pupil-linked arousal and LC processes that predict later memory separation. Boundaries, furthermore, promote temporal pattern separation within the left hippocampal dentate gyrus, which correlates with heightened LC responses to those same transition points. Unlike transient LC effects, indirect structural and functional markers of elevated background LC activation correlate with reduced arousal-related LC and pupil responses at boundaries, suggesting that hyperarousal disrupts event segmentation. Our findings support the idea that arousal mechanisms initiate a neural and memory “reset” in response to significant changes, fundamentally shaping the episodes that define episodic memory.
