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Title: Brain development in autism spectrum disorder
Author: Shahidiani, Asal
ISNI:       0000 0004 5921 1822
Awarding Body: King's College London
Current Institution: King's College London (University of London)
Date of Award: 2015
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Autism spectrum disorder is a lifelong neurodevelopmental condition accompanied by differences in brain anatomy and connectivity. Whilst the ASD brain has been widely studied under the lens of neuroimaging, results are both spatially and temporally heterogeneous. The most ubiquitous findings relate to global differences in the trajectory of early brain growth. Thus, there is a compelling need to characterize the neurodevelopmental trajectory of brain maturation in ASD beyond these early years and beneath the global level. Therefore, the present work conducts an investigation into brain development in ASD, utilizing a variety of magnetic resonance metrics in a broad sample of children and adolescents with ASD and typically developing controls. We examine age-related differences in structural connectivity - measured by diffusion tensor imaging and myelin mapping techniques - alongside vertex-based measures of cortical anatomy, including cortical thickness, surface area and gyrification. In addition, we dissect these differences within a developmental framework by investigating linear, quadratic, and cubic age effects on each neuroanatomical component in order to identify the most appropriate model for examining between-group differences in the presence of significant age effects and age ‘by’ group interactions. Finally, we extend our cross-sectional investigations by carrying out a longitudinal study of myelination in ASD, showing for the first time that the ASD is accompanied by altered myelin development. Our overarching finding is that ASD is characterised by age-related, region-specific brain differences. Importantly, these differences encompass the trajectories of both grey- and white-matter development, which we have dissected further into contributions from cortical-thickness, surface-area and gyrification, as well as white matter microstructure and myelination, respectively. Therefore, measures of grey- and white-matter morphology and connectivity should not be interpreted independently, but jointly as they jointly elicit the atypical patterns of brain development and connectivity typically observed in ASD.
Supervisor: Ecker, Christine ; Williams, Steven Charles Rees Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available