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Title: Brain connectivity in Autism Spectrum Disorder
Author: Catani, Marco
Awarding Body: King's College London (University of London)
Current Institution: King's College London (University of London)
Date of Award: 2012
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In recent years Autism Spectrum Disorders (ASD) have been considered as resulting from altered connectivity between regions, which may explain characteristic manifestations in socio-emotional function, communication and repetitive behaviour observed clinically. This thesis aims to provide evidence for altered anatomy of networks in ASD. The first step consisted in the creation of a diffusion tensor tractography atlas of the normal human brain derived from 40 healthy adults. The atlas was then used to localise the findings from a metaanalysis of published voxel-based morphometry studies investigating white matter abnormalities in ASD. This analysis showed that patients with ASD display abnormalities in long white matter association tracts, such as the arcuate and uncinate fasciculus, known to be important for language and social cognition. A second step consisted in the tractography analysis of limbic and cerebellar tracts in a small pilot study. Our findings confirmed differences in the the uncinate tract in ASD and in addition we found differences in the cingulum and major intracecebellar and cerebellar output tract. Finally, Tract-Based Spatial Statistics (TBSS) and tractography analysis of a multi-centre, case-control study was performed on 61 individuals with ASD and 61 controls. Differences in the frontal connections of the arcuate fasciculus, uncinate fasciculus, cingulum and corpus callosum were found. Tract specific measurements in the arcuate and uncinate were associated with a history of delayed echolalia and impaired used of face expression in childhood, respectively. In conclusion these series of studies show that ASD are associated with specific structural abnormalities of the limbic, language and interhemispheric white matter fibres. Differences in white matter anatomy were localised in major connections to the frontal lobe and associated with specific autistic features and traits in chilldhood. These results are compatible with the concept of ASD as a developmental frontal connectivity syndrome.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available