Reward modulation of inhibitory control during adolescence: An age related comparison of behavior and neural function
Hardin, Michael George
Fox, Nathan A
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The developmental period of adolescence is distinguished by a transition from the dependent, family-oriented state of childhood to the autonomous, peer-oriented state of adulthood. Related to this transition is a distinct behavioral profile that includes high rates of exploration, novelty-seeking, and sensation-seeking. While this adolescent behavioral profile generally aids in the transition to autonomy, it comes at a cost and is often related to excessive risk-taking behavior. Current models attribute the adolescent behavioral profile to a developmental discordance between highly sensitive reward-related processes and immature inhibitory control processes. Specifically, reward-related processes appear to develop in a curvilinear manner characterized by a heightened sensitivity to reward that peaks during adolescence. On the other hand, inhibitory processes show a protracted linear developmental trajectory that begins in childhood and continues gradually throughout adolescence. Thus, the unique developmental trajectories of these two sets of processes leave the adolescent with highly sensitive, reward-driven processes that can only be moderately regulated by gradually developing inhibitory processes. Despite the usefulness of these models of adolescent behavior, they remain incompletely supported by data, as few studies specifically examine the interaction between reward-related and inhibitory processing. The current study addresses this particular gap in the adolescent neural development literature by administering a reward-modified inhibitory control task to children, adolescents, and young adults during functional neuroimaging. Three key findings emerged from the current study. First, adolescents showed greater inhibition-related neural responses than both adults and children when potential monetary reward was available. Second, adolescents reliably showed greater striatal recruitment with reward than both adults and children. These differences in striatal response occurred as all three age groups showed significant reward-related behavioral improvements. Third, when reward was not present, adolescents and children showed deficient inhibitory behavior relative to adults. Findings from this study support models proposing interactive relationships between heightened adolescent sensitivity to reward and protracted development of inhibitory control. Additionally, the current findings expand these models by suggesting heightened adolescent sensitivity to reward may facilitate developmentally inefficient inhibitory control processes in a bottom-up manner.