Fear Not: Exploring the Role of Memory Suppression During Pavlovian Fear Extinction

The overarching aim of this thesis is to provide the first direct assessments of the retrieval stopping model of fear extinction—a model reframing century-old theories of how we overcome fears. The model marries two hitherto disconnected research areas: memory suppression and Pavlovian fear extinction. Memory suppression is a cognitive process whereby unwelcome memories intruding into our awareness are pushed out of mind, allowing us to regain control over the contents of our consciousness. Pavlovian fear extinction, on the other hand, refers to the waning of a developed fear. When something once signalled threat but no longer does, extinction is the process by which our inappropriate fear subsides over time—a process considered to be the bedrock of exposure therapy for stress- and anxiety-related disorders. Traditional conceptualisations paint extinction as a passive process—one devoid of complex cognitions, such as intrusive memories, which are at the heart of stress and anxiety conditions. The retrieval stopping model reintegrates the role of these complex cognitions within the extinction process, incorporating intrusive fear memories and efforts to actively regulate them. Using neuroimaging, behavioural, and computational modelling approaches, this thesis provides the first tests of this model, assessing both its theoretical veracity and clinical value. Chapter 1 lays the foundation for this thesis by reviewing the memory suppression and fear extinction literature, highlighting their hitherto unappreciated parallels and introducing the retrieval stopping model. To follow, Chapter 2 presents meta-analytic fMRI evidence showing that memory suppression brain networks are reliably recruited during fear extinction, supporting the idea that fear memories may be actively suppressed to regulate emotions during extinction. Chapter 3 presents a novel behavioural experiment to assess whether suppression-related phenomena spontaneously emerge during extinction and whether memory suppression may facilitate the successful extinction of fear. Chapter 4 avails of computational modelling to investigate whether instructions to suppress fear memory may bias the underlying neural mechanisms of extinction, and importantly whether this bias might be harnessed to improve clinical outcomes in exposure therapies. Finally, Chapter 5 summarises the key findings of this thesis, outlines future research opportunities, and considers currently unexplored topics, including the potential role of memory suppression in treating extinction-based disorders of addiction. Overall, in line with the retrieval stopping model, the findings support the idea that fear memories may intrude and be actively suppressed during extinction. These results provide fresh theoretical and clinical insights, offering potential improvements to treatments of fear-based disorders by deepening our understanding of how fears are overcome.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2024

Author dc:creator

• Rowlands, Molly

Advisor dc:contributor.advisor

• Anderson, Michael

• Affect regulation
• anxiety
• Emotional regulation
• exposure therapy
• extinction
• Fear conditioning
• fear extinction
• intrusions
• intrusive memories
• memory inhibition
• memory suppression
• Pavlovian fear extinction
• PTSD
• retrieval stopping
• retrieval suppression
• TNT

Licence

• https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/83b647b3-8c1c-4719-992f-825d958514b6/download
• http://purl.org/NET/rdflicense/allrightsreserved

Language dc:language

eng

DOI dc:identifier.doi

https://doi.org/10.17863/CAM.114679

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/378155