Effects of context changes on memory reactivation

• Published in: The Journal of neuroscience Vol. 44; no. 36; p. e2096232024
• Main Authors: Özdemir, Şahcan, Şentürk, Yağmur Damla, Ünver, Nursima, Demircan, Can, Olivers, Christian N L, Egner, Tobias, Günseli, Eren
• Format: Journal Article
• Language: English
• Published: United States Society for Neuroscience 04.09.2024
• Subjects: Context; EEG; Hippocampus; Long term memory; Matching-to-sample
• ISSN: 0270-6474; 1529-2401; 1529-2401
• DOI: 10.1523/JNEUROSCI.2096-23.2024

While the influence of context on long-term memory (LTM) is well-documented, its effects on the interaction between working memory (WM) and LTM remain less understood. In this study, we explored these interactions using a delayed match-to-sample task, where participants (6 Male, 16 Female) encountered the same target object across six consecutive trials, facilitating the transition from WM to LTM. During half of these target repetitions, the background color changed. We measured the WM storage of the target using the contralateral delay activity (CDA) in electroencephalography (EEG). Our results reveal that task-irrelevant context changes trigger the reactivation of long-term memories in WM. This reactivation may be attributed to content-context binding in WM and hippocampal pattern separation. Understanding the mechanisms of memory updating in response to changing contexts is vital because context plays a pivotal role in shaping long-term memories. This study demonstrates, for the first time, that an irrelevant context change triggers the reactivation of learned memories in visual working memory. This observation underscores the importance of multi-memory interactions during context updating. Challenging traditional memory models that postulate mandatory reactivation of long-term memories upon each use, our results instead reveal a selective reactivation process, especially during transitions to new environments. This finding elucidates the adaptive nature of memories and enhances our understanding of memory storage and retrieval processes.