Hickling, Alice Laura;
(2025)
The neural microcircuitry supporting event processing.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
In my PhD, I studied how the layers of the medial prefrontal cortex (mPFC) and subfields of the hippocampus form mircrocircuits to support the perception and memory of everyday experiences. Addressing this question required the high resolution offered by 7 Tesla (7T) MRI, but also brought significant challenges. I assisted the Department’s Physics Team in developing a new fMRI sequence which sought to minimise the high levels of distortion and signal drop out in mPFC. I then developed a preprocessing and analysis pipeline to detect layer- and subfield-specific multivoxel event representations. This included a tool for automating segmentation of hippocampal subfields. I applied these acquisition and analysis methods in two 7T fMRI experiments. The first examined participants while they recalled experiences from their recent and remote past. I detected representations of specific remote memories in the mPFC deep layers. This deep layer involvement suggests a role of feedback signalling from the mPFC during the remembering of remote events. In the second study, I sought to probe further the role of the mPFC in event processing. During scanning, participants watched short animated movies comprising sets of scenes viewed consecutively, that were either linked together to form meaningful events or were sets of unrelated scenes (unlinked). I found that all of the mPFC layers were engaged specifically when the events were meaningful, as were a number of hippocampal subfields, namely the dentate gyrus, Cornu Ammonis (CA)2/3, CA1 and the pre/parasubiculum. The involvement of all mPFC layers suggests that both feedforward and feedback signalling are at play during event perception. Overall, this work is starting to expose the neural microcircuitry that might ultimately lead to a full mechanistic understanding of how our experiences are initially processed, and how they often remain accessible to us in the weeks, months and years that follow.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | The neural microcircuitry supporting event processing |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2025. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/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 > UCL Queen Square Institute of Neurology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10205875 |
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