Brain Networks Involved in Higher Cognitive Functions in Adults with Autism Spectrum Disorder
Year: 2020
Type: dissertation
Study design: Observational Study
Abstract: People with autism spectrum disorder (ASD) experience difficulties with higher cognitive functions, including executive functions and theory of mind (ToM). They show atypical recruitment of brain regions involved in these functions, but functional connectivity among these areas within particular frequency bands has been less well characterized in ASD. Examining these factors is crucial to elucidating the neural mechanisms by which long-range underconnectivity and short-range overconnectivity reported in ASD influences their cognitive abilities. Therefore, this thesis used magnetoencephalography to explore the frequency-specific functional networks subserving executive functions and ToM in three studies of overlapping groups of 39 control adults and 40 adults with ASD aged 18–40 years old. Study 1 demonstrated that during inhibitory control, lower alpha-band synchrony between the right inferior frontal gyrus (IFG) and areas not typically linked to inhibition was found in adults with ASD compared to controls and was associated with everyday inhibition, suggesting weaker suppression by the right IFG of extraneous brain activity. Study 2 revealed that while connectivity did not differ between groups when maintaining stimuli in working memory, adults with ASD showed reduced theta-band network synchrony involving the right IFG and left inferior parietal lobule when recognizing previously presented stimuli. Therefore, despite intact maintenance, recognition in adults with ASD may be affected by diminished inhibition of irrelevant stimulus representations. Study 3 determined that during a ToM false-belief task, adults with ASD had lower theta-band synchrony among brain regions implicated in ToM and the right IFG, suggesting reduced inhibition of their own belief when inferring another’s false belief. Adults with ASD reported difficulties in all three functions assessed by these three studies. Together, this work suggests that reduced connectivity impacts higher cognitive functions in ASD, and that atypical inhibitory control may be a common, key contributor to cognitive difficulties in adults with ASD.
Source: TSpace (University of Toronto)
Author: Veronica Yuk
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3164247470