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The effect of common interventions on the cognitive and neural mechanisms underlying negative bias in anxiety

Lowther, Millie; (2024) The effect of common interventions on the cognitive and neural mechanisms underlying negative bias in anxiety. Doctoral thesis (Ph.D), UCL (University College London).

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Abstract

This thesis investigates the neural and cognitive mechanisms driving negative bias within anxiety and mood disorders, aiming to elucidate the impact of common interventions on these mechanisms. Negative bias is a core feature of anxiety and mood disorders, contributing to the development and maintenance of symptoms, and modification of negative bias is thought to be a mechanism underlying treatment response. This thesis specifically focuses on pessimistic interpretation of ambiguity, which is relatively understudied and the cognitive and neural mechanisms underlying this type of negative bias are not well understood. Throughout the thesis, I use a translational task to measure interpretation of ambiguity in order to bridge the gap between basic and clinical research. The first experimental chapter explores the neural circuitry underlying interpretation of ambiguity in healthy controls, using fMRI. A smaller discovery sample is used for exploratory analyses, and results are replicated in an independent larger sample. The second experimental chapter compares the neural circuitry underlying task behaviour in individuals with generalised anxiety disorder symptoms and asymptomatic controls. The third study investigates how escitalopram (a Selective Serotonin Reuptake Inhibitor), compared to placebo, modulates this bias and the underlying neural circuitry, and the fourth investigates how Cognitive Behavioural Therapy modulates the bias. The final experimental chapter investigates the cognitive mechanisms contributing to bias in the task, with a focus on potential feedback-based learning processes. The general discussion chapter discusses these findings in relation to contemporary models of antidepressant action and cognitive behavioural therapy, considering implications of the results, limitations of the work presented, and possible future directions.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: The effect of common interventions on the cognitive and neural mechanisms underlying negative bias in anxiety
Language: English
Additional information: Copyright © The Author 2024. 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 > Div of Psychology and Lang Sciences
URI: https://discovery-pp.ucl.ac.uk/id/eprint/10197391
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