Date of Award

Spring 5-2021

Degree Type

Dissertation

Degree Name

Ph.D.

Degree Program

Applied Biopsychology

Department

Psychology

Major Professor

Elliott Beaton, PhD

Second Advisor

Carl Weems, PhD

Third Advisor

Tracey Knaus, PhD

Fourth Advisor

Deidre Devier, PhD

Abstract

Schizophrenia spectrum disorder (SCZ) is a debilitating psychiatric disorder that affects approximately 1% of the general population. The etiopathology of this disorder is not fully understood with genetic and environmental factors underpinning vulnerability and disease progression. Children with chromosome 22q11.2 deletion syndrome (22q11.2DS) are at ultra-high risk for developing SCZ with 30% developing the disorder in adolescence or young adulthood. To investigate associations with psychosis vulnerability, much work has been performed looking at neurological underpinnings between schizophrenia and 22q11.2DS to assess similarities between both genetic and idiopathic forms of schizophrenia in adults. However, many past studies have assessed this using isolated/region of interest assessments, which may miss more nuanced aspects of the ’dysconnectivity’ component of schizophrenia. One such method that incorporates a network approach to observation and assessment is that of graph theory, which is implemented on a matrix/network representation of the cortex, parcellated into meaningful regions, known as the connectome. In the current study, 39 individuals with 22q11.2DS and 38 age- and sex-matched healthy controls (HC) ages 7 to 17 years old, were assessed for anxiety and behavioral issues and performance on an emotional face processing task. Regional volumetric and white matter connectivity differences where compared between groups in relation to anxiety, behavior, and task performance. Children with 22q11.2DS had more behavioral problems and anxiety with poorer performance on the face task. Brain morphometric differences in relation to task performance and psychological measures included the anterior and posterior cingulate and the pericalcarine gyrus. Anxiety and behavioral problems were additionally associated with group differences in temporal and postcentral gyri. Children with 22q11.2DS had increased neural connectivity relative to HC in many brain regions but a clustering coefficient difference was evident in the right nucleus accumbens. Overall, the current study highlights the importance of midline structures in both group differences and their association with predicting emotion performance and clinical/behavioral issues, highlighting the nuanced information that can arise when utilizing a graph theory approach. This is the first study to appraise the association of connectome metrics with emotion performance and behavioral issues beyond psychosis in a pediatric sample of individuals with 22q11.2DS.

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The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.

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