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Context Modulated Spatial Encoding and Memory Consolidation in the Rodent Hippocampus

Tirole, Margot Fiona; (2021) Context Modulated Spatial Encoding and Memory Consolidation in the Rodent Hippocampus. Doctoral thesis (Ph.D), UCL (University College London).

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Abstract

The recollection of daily events is inherently personal: episodic memories are defined by the recollection of one’s sense of self during a particular event, within a surrounding context. Representations of such experiences are initially encoded in the hippocampus then consolidated by their repeated reactivation in synchrony with the cortex during sleep. After consolidation, memories are less prone to interference by similar experiences. However, a day in one’s life is usually constructed from multiple episodic experiences which can span multiple contexts. Little is known about the potential interference by previous memories on the construction of novel representations when contextual features are shared. Moreover, salient episodic memories are better remembered than neutral ones in the long term. Highly rewarding, traumatic or novel experiences can lead to intrusive (e.g. Post Traumatic Stress Disorder) or extremely vivid recall (e.g. Flashbulb memories) recall, and in general longer lasting memories. This phenomenon of prioritised memory consolidation is thought to ensure the storage of relevant memories, at the detriment of less important ones, and has been shown to correlate with an overall increase in their reactivation frequency during sleep. However, the temporal dynamics of memory triage during sleep have not yet been investigated. Recording from many hippocampal neurons simultaneously in the rat, during both sleep and the exploration of three completely new environments each session, we tracked the encoding and consolidation of feature-sharing and salience modulated representations. We provide evidence for the presence of neural patterns of activity that may support generalisation with similar past experiences, as well as differentiation of the novel representation during its initial stabilisation window. Furthermore, we show that the temporal dynamics of memory triage are not uniform, and instead exhibit a cyclic (time attributed to each memory) and an amplitude (relative proportion) component.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: Context Modulated Spatial Encoding and Memory Consolidation in the Rodent Hippocampus
Event: UCL (University College London)
Language: English
Additional information: Copyright © The Author 2021. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) Licence (https://creativecommons.org/licenses/by-nc-nd/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request.
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences > Experimental Psychology
URI: https://discovery.ucl.ac.uk/id/eprint/10133594
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