All ETDs from UAB

Advisory Committee Chair

Rajesh K Kana

Advisory Committee Members

Edwin W Cook

David C Knight

Sarah E O'Kelley

Kristina M Visscher

Document Type

Dissertation

Date of Award

2015

Degree Name by School

Doctor of Philosophy (PhD) College of Arts and Sciences

Abstract

Deficits in language comprehension have been widely reported in children with autism spectrum disorders (ASD). Recent evidence from neuroimaging research has found that individuals with ASD tend to recruit visuospatial imagery to comprehend language (Kana et al., 2006). The theory of cortical underconnectivity in autism suggests that in tasks that can be interpreted either visually or verbally, brain regions associated with language and visuospatial processing will be substantially less functionally integrated (especially between frontal and more posterior regions) than healthy-matched controls (Just et al., 2004). Indeed, cortical underconnectivity in individuals with ASD has been documented, not only in extrinsic brain activation, but have also been seen during intrinsic brain activation (Cherkassky et al., 2006; Kennedy & Courchesne, 2008a,b). Evidence from these studies suggests that despite relying on visuospatial imagery to interpret language, individuals with ASD may have problems in the coordinated functioning of brain regions. The proposed project used an imagery-based intervention program to improve the brain circuitry underlying language processing and its integrated functioning in children with ASD by tapping into visuospatial processing to improve language comprehension. We use resting state as well as task-based functional MRI to study the neurobiological mechanisms of language impairments in children with ASD, and to test whether a language remediation program can change the brain circuitry in ASD. Our first study investigates the link between visuospatial abilities and language comprehension in children with ASD and found increased activation post-intervention of visual and posterior language regions, as well as right-hemisphere language homologous regions, precentral gyrus (PrCG), postcentral gyrus (PoCG), putamen, and thalamus, as well as, strengthened functional connectivity between left hemisphere language areas, the middle temporal gyrus and inferior frontal gyrus. Our second study assesses the reading network using intrinsic resting state functional connectivity. We found neural changes specific to intervention of stronger functional connectivity of both Broca's and Wernicke's areas in the children with ASD post-intervention. Overall, these novel findings provide valuable insights into the plasticity of brain's language networks and have strong implications for individualization of treatment for children with ASD.

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