Neural Basis of Pragmatic Language Processing in Autism Spectrum Disorder

Difficulties in pragmatic language processing are recognized as a key symptom of autism spectrum disorder (ASD). Despite this acknowledgment, the neurophysiological mechanisms underlying these difficulties, particularly in children with ASD, remain unclear. This thesis investigates the neural bases of pragmatic language processing in children with and without ASD. It is hypothesized that the challenges in pragmatic language processing in ASD are related to disrupted brain functioning and communication between brain areas. This thesis examines event-related potentials (ERPs) using EEG and brain connectivity using fMRI.

The first study introduces a novel data collection method, "The Science Camp Research Experience," which details the process of conducting a science camp to obtain behavioural and electrophysiological data. This method leverages positive peer interactions and engaging activities to collect data effectively from diverse groups of children. The second study focuses on pragmatic language processing in children with and without ASD, using ERPs linked to language processing (N400 and P600). Results highlight significant neural response differences in children with ASD compared to typically developing (TD) children despite similar reaction times and accuracy rates.

The third study explores brain functional connectivity during a pragmatic language task centred around speech acts. Children with ASD exhibit distinctive connectivity patterns in the left Somatomotor and left limbic networks. The fourth study employs a multivariate statistical approach to identify associations between these connectivity patterns and cognitive abilities. Both groups exhibited brain-behaviour correlations. However, the nature of these associations diverged. Our findings suggest that children with ASD utilize distinct neural communication patterns for language processing.

Overall, this thesis underscores that children with ASD utilize unique neural communication strategies for language processing, which may serve as compensatory mechanisms for potential disruptions in conventional brain networks. The findings contribute to understanding the neurobiological underpinnings of pragmatic language difficulties in ASD and shed light on this population's distinct neural processes involved in pragmatic language processing.