Longitudinal changes in Go/No-Go and Stop Signal Task performance and relationships with gray matter architecture in adolescent development

Abstract

This dissertation explores the development of response inhibition in adolescence to better understand risk-taking behaviors and risk for psychopathology. The first aim is to evaluate the longitudinal developmental trajectory of motor response inhibition among healthy adolescents and young adults using two tasks. The second aim is to explore relationships between regional gray matter architecture with individual differences and development of response inhibition. Research in this area has predominantly relied upon cross-sectional studies, used only one response inhibition task, lacked exploration of non-linear models, and rarely explored structural brain correlates of response inhibition. To address these limitations, this dissertation incorporated a longitudinal cohort sequential design (baseline ages 11 – 24, N = 148, up to four timepoints two years apart) to assess performance on two response inhibition tasks. Analyses included nonlinear models, retest stability estimates, and examination of between- and within-subjects associations of response inhibition with gray matter architecture. In Study 1, response inhibition as measured by the Stop Signal and Go/No-Go tasks demonstrated an inverse age trajectory with steepest improvements in early adolescence followed by stabilization. Neither task demonstrated sex effects, and each had fair retest stability. Building upon Study 1, Study 2 found that gray matter architecture of the inferior frontal gyrus was related to response inhibition. Distinct associations among gray matter measures, response inhibition tasks, and specific subregions of the inferior frontal gyrus were found. Collectively, this work characterizes the normative pattern of development of response inhibition in adolescence and identifies early adolescence as a specific period of plasticity and potential vulnerability that may be associated with gray matter development in the inferior frontal gyrus. It suggests that motor response inhibition is not a likely candidate for explaining peaks in risk-taking that occur in later adolescence. This work provides evidence for similarities and differences between the Go/No-Go and Stop Signal tasks and demonstrates strengths and weaknesses of each that may guide future research.