Adolescence is a period of the lifespan when challenges to behavioral regulation can have critical short and long-term repercussions. During adolescence, burgeoning independence and exposure to situations that entail tangible risk (access to alcohol, drugs, or cigarettes) present a particular psychological challenge, whereby momentary motivation toward potential rewards comes into conflict with long-term goals that require inhibitory control processes. Though risky decision-making remains a key public health issue in adolescence, there is not a clear consensus on how to best design public health interventions to support decision making in adolescence. If we understood the mechanisms of inhibitory control, specifically in the face of rewarding stimuli we could create more effective interventions around risk in adolescence. Age related variability in self-regulatory behavior and resulting risky behavior during adolescence has been historically attributed to age-related deficits in inhibitory control and still-maturing lateral prefrontal systems, such as the right infrior frontal gyrus. However, recent neuroimaging studies have challenged this view (for a review, see Somerville, Jones, & Casey, 2010). For example, most motor inhibitory control tasks improve during adolescence, instead of declining. However, one study revealed that adolescents (relative to children and adults) were selectively less skilled at engaging in impulse control to positive social cues (happy faces) and showed different associated patterns of activity in the ventral striatum (VS). While this evidence suggests that increased risk behavior during adolescence may stem from adolescent-specific challenges in employing inhibitory control over rewarding cues, this task relies heavily on social stimuli (smiling faces), which come with their own variable reactions, known to be influenced by early childhood experiences and onset of adolescence. Here we address these gaps in the literature by introducing a novel test of inhibition of reward Learned Reward Inhibition Task (LRIT) and propose to investigate the neural correlates of the developmental progression of inhibition of reward across late childhood, early adolescence, late adolescence and adulthood using structural and functional MRI. Our preliminary data suggest differences between children and adolescents in control over previously rewarded, socially irrelevant stimuli. In children, inhibition is facilitated for these stimui, while it is selectively impaired in adolescents. That is, in the LRIT task, children are moe able to withhold a response from a previously rewarded cue. In contrast, adolescents are less able to withhold a response from a previously rewarded cue. This task, relative to other assessments of inhibitory control, appears to isolate a deficit in adolescent cognition, relative t children that more closely aligns with the dramatic uptick in risk taking and self reported impulsivity in adolescence.
To date, studies of the neural correlates of inhibitory control during adolescence have clear limitations and are poorly understood, representing a gap in knowledge with implications for a major public health concern. Here we address this gap in the literature by introducing a novel test of inhibitory control over reward: Learned Reward Inhibition Task (LRIT) and propose to investigate the neural correlates of the developmental progression of inhibitory control over adolescence and associations with substance use/abuse. This task, relative to other assessments of inhibitory control, isolates deficits in adolescent cognition, relative to children that most closely aligns with the dramatic uptick in risk taking and self reported impulsivity in adolescence.
