Investigating how APOE differentially affects memory and perception of ambiguous scenes in young- and middle-aged adults

Jones, Matthew Thomas 2018. Investigating how APOE differentially affects memory and perception of ambiguous scenes in young- and middle-aged adults. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

My thesis investigated whether performance on complex scene and object perceptual and memory tasks would be influenced by possession of different variants of the APOE gene. A particular focus was on the effect of the APOE-e4 allele on scene processing. APOE-e4 is known to increase risk for Alzheimer's disease (AD) in later life and is associated with structural and functional changes in the medial temporal lobe (MTL) and posteromedial cortex, regions known to be affected early in AD. Previous studies have shown sensitivity to spatial processing in AD, including difficulties in differentiating scene, but not object, stimuli (Lee et al., 2006), impairments remembering scenes over a delay (Bird et al., 2010), and deficits in navigation around spatial environments (Pengas et al., 2010). These findings suggest that difficulties with complex spatial processing may be a hallmark of AD, and that investigation of scene processing in individuals at greater risk of developing AD later in life may be of interest in understanding the genesis of these later life cognitive impairments. In Chapter 1, I provide an overview of relevant literature on the APOE gene and its relationship to AD, and discuss experiments which have demonstrated brain and behaviour differences between APOE-e4 carriers and non-carriers. I interpret these findings in the context of recent models of memory which focus on representational networks, and where distinctions between scene and object processing are a key feature (Bussey & Saksida, 2007; Graham, Barense, & Lee, 2010; Murray, Wise, & Graham, 2017). The subsequent chapters describe experiments which aimed to extend the research described in Chapter 1 by investigating scene perception and memory in carriers of different APOE alleles in early- and mid-adulthood. In Chapter 2, I describe findings from applying a novel conjunctive learning task, in which participants were required to discriminate between objects and scenes. In Chapter 3, I report results from applying a new visual paired-comparison task in the same group of participants. Chapter 4 extends the approach outlined in Chapter 3, using the visual paired-comparison task in middle- aged participants, again focusing on the comparison of performance in groups with different APOE genotypes. Finally, in Chapter 5, I assess how performance in the tasks used in Chapters 2-4 are related to the volumes of brain regions (in the MTL and extrastriate cortex). As these have been strongly linked to object and scene perception and memory, I was interested in whether volume would be associated with performance on my new tasks. The final chapter summarises the experimental findings from Chapters 2-5 and explains how these build upon our current body of knowledge about how the APOE gene affects cognition in both early- and mid-adulthood.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Psychology
Subjects:	B Philosophy. Psychology. Religion > BF Psychology
Funders:	WIN ESRC
Date of First Compliant Deposit:	12 March 2019
Last Modified:	31 Jan 2020 03:22
URI:	https://orca.cardiff.ac.uk/id/eprint/120587

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