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Title: Visual information processing during self-motion : neural mechanisms investigated using fMRI
Author: Inman, Laura Anne
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2013
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The research reported in this thesis aimed to further the understanding of brain regions implicated in the visual processing that supports self-motion. Four fMRI investigations were conducted. The first three investigations were focused on exploring the functional response properties of the dorso-medial superior parietal lobule (dmSPL). This region was previously implicated in processing so-called 'future path' information during locomotion, but Experiment I refuted this hypothesis, and suggested that dmSPL processes a more general type of visual information. Experiments 2 and 3 confirmed the region was not specialised for visual self-motion processing, and suggested the novel idea that the region is implicated in processing the changing visual distances and angles between objects (relative position). This is a valuable type of information processing in the context of supporting self-motion, and this hypothesis can also explain published reports of dmSPL activation from multiple contexts. However, an alternative view of the region, which data presented here cannot rule out is that dmSPL is active whenever spatial attention is shared between multiple locations. In contrast to the first three studies, Experiment 4 was an exploratory study of the functional properties of the putative human ventral intraparietal region (hVIP). Previous reports of the region suggested that it responds to optic-flow produced by self-motion. Although this was observed in this investigation, activation was further raised in response to simulated motion of objects in the environment. Importantly, when the visual motion of an object was clearly due to the self-motion of the observer, signal change in h VIP was not raised relative to that to simulated optic-flow alone. Considering these results in the context of the literature, it is possible that h VIP is primarily responsive when object motion occurs in the near-space around the observer, indicating potential collision, although further investigation is needed to verify this.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available