Impulsivity

Impulsivity is a multifaceted construct associated with semi-distinct neurological substrates in the general population and individuals diagnosed with psychiatric conditions. ADHD is a complex neurodevelopmental disorder with significant impulsive symptoms which persist into adulthood. Impulsivity is measured using task-based (impulsive actions and impulsive choices) and self-report trait-based measures. However, how task-based and self-report measures relate across diagnostic groups, including adults diagnosed with ADHD, is unclear. Further, our understanding of the structural neural circuits associated with these task-based and self-report measures of impulsivity is incomplete. Finally, the striatum has a distinct topological relationship with cortical and subcortical structures. Specifically, the striatum acts as a hub connecting cortical and subcortical regions. However, it is unknown what the relationship is regarding the topology of the striatum and impulsive behaviors. In this dissertation, we put forward three aims: 1) To examine the relationship between task-based impulsive behaviors and trait-based impulsivity, 2) To examine the underlying white matter associated with task-based and trait-based impulsivity, and 3) To describe the topological properties of the striatum and their relationship to impulsive behaviors. We conclude that 1) measures of impulsivity are mostly unrelated, 2) task-based and trait-based measures of impulsivity are associated with distinct structural neural circuits, and 3) the striatum is an important integrator of information related to some impulsive behaviors. This dissertation concludes by putting forward some possible recommendations to researchers and clinicians to improve the discourse surrounding impulsivity clinically and in research and suggests directions for future research in impulsivity.