Cinematic scanning: using movie watching fMRI to investigate the function and organisation of the visual brain

Wells, Mason 2022. Cinematic scanning: using movie watching fMRI to investigate the function and organisation of the visual brain. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Visually responsive brain regions and networks/pathways are traditionally examined using non-naturistic stimuli and time-consuming tasks. In this thesis, I investigate an alternative approach that uses a stimulus more closely resembling our typical visual input, a Hollywood movie. First, I explore the chronotopy approach (Bartels & Zeki, 2004b, 2005b), which seeks to segment the brain into visually responsive regions using a combination of independent component analysis (ICA) and movie watching fMRI data. I find a simple division of the brain into visual sub-regions does not hold up for all visual areas. Instead, I find a high amount of variability across brains and across visual areas. Second, through a series of timecourse correlation analyses and ICA, I investigate Strong et al.’s (2019) hypothesis that the two hemispheres have different functional roles in the processing of visual motion. At the group-level, I find only weak supporting evidence of the hypothesis. However, the examination of individual brains did allow me to identify some functional differences between hemispheres for a small number of subjects. Third, I use ICA to look for evidence of a hypothesised third visual pathway dedicated to the processing of visual motion, the lateral motion pathway (Gilaie-Dotan, 2016). Group-level ICA provides evidence of a partitioning of the brain into distinct networks which support the three visual pathway model, which were subsequently found in over 50% of brains at the single-subject level. Individual differences are clear with each analysis I performed, supporting a growing area of research that aims to examine brain function and organisation at the individual level. Finally, I describe a psychophysics experiment designed to systematically investigate retained motion processing in patients with cortical vision loss.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Optometry and Vision Sciences
Subjects:	R Medicine > RE Ophthalmology
Uncontrolled Keywords:	Visual neuroscience, fMRI, neuroimaging, movie watching, naturalistic stimuli, motion processing, lateralisation, hMT+, visual pathways, residual vision, blindsight, chronotopy, ICA, inter-subject correlation, psychophysics
Date of First Compliant Deposit:	27 June 2022
Last Modified:	27 Jun 2023 01:30
URI:	https://orca.cardiff.ac.uk/id/eprint/150811

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