Incentive Processing and Inhibitory Control in Adolescents and Young Adults

Adolescents are known to demonstrate normative increases in risk-taking behaviors. Understanding the interaction between incentive (reward, punishment) processing and basic cognitive control abilities, both of which are still maturing into adolescence, may provide insight on the basic mechanisms contributing to this complex behavioral phenomenon. In this dissertation, we present a compilation of papers aimed at characterizing the influence of potential reward gain or loss on response inhibition performance and supporting brain circuitry in adolescents and adults. In study 1, we use fast, event-related functional magnetic resonance imaging (fMRI) to examine the neural circuitry supporting perfomance on an antisaccade task with reward or neutral contingencies added to each trial. Results indicate that components of the adolescent reward system exhibit an initially sluggish, then eventually overactive response to rewards, as well as limited recruitment in regions supporting the executive assessment of rewards. In study 2, the effects of different magnitudes of potential gains and losses on antisaccade task performance were examined. Results indicate that higher compared to lower magnitude reward contingencies differentially affect adolescent, but not adult, response suppression abilities. Furthemore, both age groups performed consistently well (low error rates) on punishment trials. In study 3, adolescents and adults underwent fast, event-related fMRI as they performed a rewarded antisaccade task with fixed-magnitude reward and punishment stimuli, previously determined to result in equivalent levels of behavioral performance across the age groups (study 2). Additionally, auditory, performance-based feedback was provided on each trial. fMRI results indicate that during detection of reward cues, adolescents do not show the same early recruitment of oculomotor control regions evident in adults. Furthermore, adolescents demonstrated temporally extended responses in several brain regions (e.g., orbitofrontal cortex, supplementary eye field) during the preparatory period of potential punishment trials, reflecting possible immaturities in mechanisms underlying potential loss or 'risk' anticipation. Finally, adults demonstrated enhanced activity in the ventral striatum and cortical eye fields during the response/feedback epoch, suggesting more mature consummatory processing. Collectively, the results of these studies demonstrate protracted development of higher-order executive aspects of reward processing and its interaction with response inhibition abilites into adolescence