Autism is a life-long neurodevelopmental condition. Autistic individuals have
difficulties in communicative and social ability, and repetitive and stereotypic
behavior. It has proposed that these symptoms are caused by underconnectivity in the
autistic brain. Functional imaging studies have reported functional underconnectivity
in autism. In this thesis, the structural connectivity of the autistic brain was studied.
White matter contains axon fibers, which connect different cortical and subcortical
brain regions. To measure the structural connectivity, Diffusion tensor imaging (DTI)
was applied. Since water diffusion in axons inside the white matter is directional, by
measuring the magnitude and direction of water diffusion in white matter, the
structural integrity of white matter fibers could be estimated.
In this thesis, the background of autism as a genetic, neurological and behavioral
condition is outlined. The methods needed to acquire and analyze DTI data are
illustrated. A meta-analysis on abnormalities found in autistic brain using DTI was
conducted and the most consistently reported regions with DTI differences in autism
compared to typically developing controls are described. The results of the metaanalysis
were localized to white matter tracts likely to be involved, and the possible
associations between anatomy and autistic behavioral features are discussed. Finally,
a DTI tractography study was conducted in a sample but clinically representative
sample of patients with ASD and eighteen major white matter tracts were explored.
Underconnectivity in several tracts was identified. It is hoped that the findings
reported here will enhance our understanding of widespread underconnectivity in
autism. / published_or_final_version / Psychiatry / Master / Master of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/174385 |
| Date | January 2012 |
| Creators | Wong, Ho-yin, 黃浩然 |
| Contributors | Chua, SE, McAlonan, GM |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Source | http://hub.hku.hk/bib/B47326165 |
| Rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License |
| Relation | HKU Theses Online (HKUTO) |
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