UCLA

Adolescence is a period of dynamic change in nearly every domain. This developmental transition is characterized by dramatic alterations in hormone levels, remodeling of neural circuitry, and a number of behavioral changes including increased risk taking. In this dissertation, I present a multi-method program of research investigating the neurobiological contributors to adolescent risky decision-making in a sample of 14-18 year old adolescents (N=55). Taken together, findings suggest that the adolescent brain may be influenced by distinct hormones during specific aspects of decision making, and provide novel evidence for the possibility of a unique role for DHEA in cautious decision-making processes. Specifically, my research demonstrates that testosterone is related to trait measures in adolescents, replicating previous studies linking testosterone with sensation seeking and risk attitudes toward sexual behavior. During a novel laboratory paradigm, testosterone is associated with neural response preceding the selection of a risky choice, and DHEA with neural response preceding the selection of a cautious choice. Moreover, DHEA is associated with greater connectivity between the dorsolateral prefrontal cortex, a region implicated in regulatory processes, and regions of the brain including the ventral striatum, a region implicated in reward processing. In other words, adolescents with higher levels of DHEA exhibit greater frontostriatal connectivity when making decisions under conditions of risk. Finally, this research demonstrates that recruitment of neural circuitry during selection of cautious choice is related to individual differences in self-reported risky sexual behavior (i.e., lifetime condom use), providing support for the ecological validity of the laboratory task and relevance to behaviors important for public health.