Functional and structural properties of spatial processing networks in the brain

Read, Marie-Lucie 2021. Functional and structural properties of spatial processing networks in the brain. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

The Perceptual-Mnemonic (PM) view of the Medial Temporal Lobe (MTL) suggests it processes representations for both perception and memory and that functional separation in its regions echoes differing modality specialisation of two widespread networks. This thesis investigated a Posteromedial Network (PMN) facilitating spatiotemporal navigation, contrasting it with an Anteroinferior Network (AIN) facilitating aggregate object/face processing. 3 Supporting the PM-view, previous work reported correlations between network tract microstructure, functional magnetic resonance imaging-measured MTL signals and perceptual performance. However: the microstructure measures were biologically non-specific; no studies used magnetoencephalography (more temporally precise); the relative importance in MTL-reliant behaviours of PMN tracts that connect different MTL areas were uninvestigated; and studies relating PMN network structure to temporal processing produced conflicting results. 4 This project investigated relationships between inter-individual differences in behaviour and these networks’ structures and functions using perceptual and mnemonic tasks probing perception of scenes and faces, and memory of objects-in�sequences. Microstructure measures were reduced into biologically interpretable components. Those of the fornix – a proxy of hippocampal-PMN communication – correlated with scene perception and object-in-sequence memory performance. Those of the parahippocampal cingulum, which connects other PMN areas, did not, indicating the specific role of the hippocampus in spatiotemporal representation. Those of the inferior longitudinal fasciculus, part of the AIN, correlated with face perception performance. PMN theta/gamma power modulation occurred more during scene perception than face perception. In-task MTL theta power modulation (reflecting hippocampal/parahippocampal processing), and PMN - posterior cingulate cortex resting-state connectivity correlated with scene perception performance. Conversely, AIN theta/gamma power modulations occurred during face perception. These imply that MTL regions are important for both perception and memory and that two dissociable networks cater for the different modalities. An implication of the findings is that MTL damage (e.g., as occurs in Alzheimer’s Disease) may not produce purely memory disorders but impair representations for use across behaviours.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Psychology
Subjects:	B Philosophy. Psychology. Religion > BF Psychology
Date of First Compliant Deposit:	17 September 2021
Date of Acceptance:	17 September 2021
Last Modified:	17 Sep 2021 14:38
URI:	https://orca.cardiff.ac.uk/id/eprint/144261

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