Biyolojik temeller, bilişsel süreçler ve davranışlar üzerinden otizmi anlamak

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with increasingly rising prevalence, where as of 2018, 1 in 59 children is reported to have ASD. ASD has no known cause or treatment, or a broad theory that accounts for all its behavioral and physiological manifestations. Thus, comprehensive investigations across multiple domains are important for understanding ASD, which is the focus of the present thesis that explores the biological basis, cognitive signature, and behavioral problems in individuals with ASD. Firstly, this thesis investigated the two risk factors of gut dysbiosis and inflammation in ASD together and revealed potential common mechanisms of action for these two risk factors, which are their effects on neurodevelopment, ASD gene expression, and gut and brain barrier integrity. This then segued into suggesting probiotics as a potential treatment or prevention that can target all these areas that are possibly influenced by ASD risk factors to result in the ASD phenotype. Secondly, the unique cognitive style of individuals with ASD was investigated empirically with a thorough design that explored error-monitoring in two cognitive domains of decision-making and timing. Results revealed a circumscribed deficit in error-monitoring in the presence of similar task performance with typically developing (TD) controls. Thirdly, the relationships between parent psychological problems and child behavior problems were investigated in families with children with ASD and TD children. It was found that parent obsessive-compulsive characteristics predicted child ASD symptoms. Overall, this thesis contributes to understanding ASD by offering novel findings about its biological basis, cognitive signature, and behavioral inheritance profile, which can guide investigations into more comprehensive models that may one day be able to explain this complex disorder.