Adolescence is a period of the lifespan when challenges to behavioral regulation can have critical short and long-term repercussions including increased risk for substance abuse. To date, studies of the neural correlates of inhibitory control during this period have clear limitations and are thus poorly understood, representing a gap in knowledge with implications for a major public health concern. If we understood the mechanisms of inhibitory control, specifically in the face of rewarding stimuli, we could create more effective preventive interventions. Here we address this gap in the literature by introducing a novel test of inhibitory control over reward: Habitual Appetitive Behavior Inhibition Task (HABIT) and propose to investigate the neural correlates of the developmental progression of inhibitory control over reward in late childhood, early adolescence, late adolescence and adulthood using structural and functional magnetic resonance imaging. We further propose investigating the relationship between neural structure and function and self-reported substance use and abuse during adolescence. 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
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 (driving, 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 deficits in inhibitory control and still-maturing lateral prefrontal systems, such as the right inferior frontal gyrus (rIFG). However recent neuroimaging studies have challenged this view (for a review, see Somerville, Jones, & Casey, 2010). For example, 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 and other tasks available to examine inhibitory control over reward have two problematic aspects. First, this task relies heavily on social stimuli, such as smiling faces, which come with their own variable learning history related to reward, known to be influenced by early childhood experiences. Second, adolescence is a period of extreme sensitivity to the social environment. Thus, observed differences in inhibitory control over reward and associated neural activation may simply be accounted for by individual differences in learning history and/or developmental differences in sensitivity to social stimuli. Here we address these gaps in the literature by introducing a novel test of inhibition of reward Habitual Appetitive Behavior Inhibition Task (HABIT) 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 magnetic resonance imaging. Our preliminary data suggest differences between children and adolescents in control over previously rewarded, socially irrelevant stimuli, where the learning history is well controlled. In children, inhibition is faciltated for these stimuli, while it is selectively impaired in adolescents. That is, in the HABIT task, children (ages 4 to 12 years) are more instead of less able to withhold a response from a previously rewarded cue. In contrast, adolescents (age 13-17 years) 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 to children that more closey aligns with the dramatic uptick in risk taking and self-reported impulsivity in adolescence.
