| dc.description.abstract | When brain networks deviate from typical development, it is thought to contribute to varying forms of psychopathology. However, research has been limited by the reliance on discrete diagnostic categories that overlook the potential for psychological comorbidity and the dimensional nature of symptoms. Study 1 examined the topology of functional networks in association with four psychopathology dimensions—general psychopathology, internalizing symptoms, conduct problems, and attention-deficit/hyperactivity disorder (ADHD) symptoms—via the Child Behavioral Checklist in a sample of 3,568 children from the Adolescent Brain Cognitive DevelopmentSM Study (ABCD Study®). Local and global graph theory metrics were calculated at rest and during tasks of reward processing, inhibition, and working memory. Consistent across rest and tasks, Study 1 showed greater ADHD symptoms were associated with reduced modularity and reduced local efficiency in motor networks at rest. Results survive sensitivity analyses for medication and parental education. Greater conduct problem symptoms were associated with reduced modularity on tasks of working memory and reward processing; however, these results did not persist after sensitivity analyses. General psychopathology and internalizing symptoms showed no significant network associations. Study 2 then quantified core features of ADHD—inattention and hyperactivity/ impulsivity—to examine functional topology associated with ADHD subtypes. Findings indicated that inattention and hyperactivity/impulsivity features of ADHD largely overlap in functional network properties. However, findings suggest that greater inattentive features were associated with poorer efficiency as measured by lower small worldness in the visual II network during the reward processing task, while greater hyperactivity/impulsivity features were associated with greater small worldness in the visual II network. Overall, the present thesis’ findings suggest reduced efficiency in forming communication hubs in those with greater ADHD symptoms across four critical cognitive states, with conduct problems also showing network deficits, although less consistently. This may suggest modularity deficits are a neurobiological marker of externalizing behavior in youth. Further, findings show that inattentive and hyperactive/impulsive features of ADHD largely overlap in functional network properties, with the exception of the primary visual network. Taken together, this has the potential to refine our understanding of network deficits in children with psychopathology symptoms, particularly externalizing symptoms. | |
