sensitivities to drug-related rewards as well. Clearly, more research is needed to resolve these issues, with perhaps particular attention directed toward need state, as well as modality and relative intensity of reward. Indeed, when using fMRI to compare NAc activation to rewards in human adolescents and adults, Galvan and colleagues (2006) found the relationship between NAc activation and reward magnitude normally seen in adults to be exaggerated during adolescence, with adolescents showing more dramatic increases in NAc recruitment with larger rewards than adults, but tending to show weaker recruitment in response to small rewards. Together, fMRI studies of reward sensitivity of human adolescents, combined with further studies using basic animal models of adolescence, may provide important information as to the affective significance of potentially rewarding stimuli and their impact on reward-directed behaviors during adolescence compared to adulthood.
