What Motivates the Adolescent? Brain Regions Mediating Reward Sensitivity across Adolescence

TLDR

Adolescents’ risky behavior has been linked to brain development, with theories suggesting a developmental imbalance between the striatum and prefrontal cortex makes them hypersensitive to reward. The study aimed to determine whether adolescents’ risk‑taking stems from overestimating potential rewards or heightened responses to received rewards, and whether these effects occur even without decision‑making. Using fMRI, the authors compared reward anticipation, receipt, and omission across 10‑12‑, 14‑15‑, and 18‑23‑year‑olds to isolate neural responses to each reward phase. They found adolescent anticipation activated the anterior insula, middle adolescence peaked in the ventral striatum, young adults showed orbitofrontal activation to omitted reward, and these distinct developmental trajectories confirm adolescents’ reward hypersensitivity and its relevance to risk‑taking.

Abstract

The relation between brain development across adolescence and adolescent risky behavior has attracted increasing interest in recent years. It has been proposed that adolescents are hypersensitive to reward because of an imbalance in the developmental pattern followed by the striatum and prefrontal cortex. To date, it is unclear if adolescents engage in risky behavior because they overestimate potential rewards or respond more to received rewards and whether these effects occur in the absence of decisions. In this study, we used a functional magnetic resonance imaging paradigm that allowed us to dissociate effects of the anticipation, receipt, and omission of reward in 10- to 12-year-old, 14- to 15-year-old, and 18- to 23-year-old participants. We show that in anticipation of uncertain outcomes, the anterior insula is more active in adolescents compared with young adults and that the ventral striatum shows a reward-related peak in middle adolescence, whereas young adults show orbitofrontal cortex activation to omitted reward. These regions show distinct developmental trajectories. This study supports the hypothesis that adolescents are hypersensitive to reward and adds to the current literature in demonstrating that neural activation differs in adolescents even for small rewards in the absence of choice. These findings may have important implications for understanding adolescent risk-taking behavior.