Despite the fact that all adolescents

Despite the fact that all adolescents undergo development of these social and neural systems, engagement in risky behavior varies, with some far more likely than others to partake (Bjork and Pardini, 2015). One likely factor underlying individual differences in risk-taking behavior is function in social neurocircuitry (Victor and Hariri, 2016). Such differences may contribute to individual variability in motivation to experience the benefits of risky behavior, and in the extent to which the presence of peers affects risky decision-making (Albert et al., 2013). Notably, neural response to risky decisions is associated with future real-life engagement in such behavior (Crowley et al., 2015). Consistent with proposed models involving heightened reward motivation and reactivity, higher tendency toward impulsivity is consistently linked to adolescents’ risky sexual behavior (Dir et al., 2014), and greatervs activation has been observed in adults with compulsive sexual behaviors (Voon et al., 2014). Despite the likely involvement of neural reward circuitry in risky sexual behavior, the literature on its role in adolescent sexual risk-taking is scant. One recent study in young adults ages 18–22 found that increasing ventral striatum activation during reward predicted the number of sexual partners (Victor et al., 2015). In contrast, the majority of available studies have examined inhibitory control, demonstrating a relationship between risky sexual behavior and weaker lateral prefrontal cortex response during response inhibition (Ewing et al., 2015; Goldenberg et al., 2013). No studies have examined functional connectivity in adolescent risky sexual behavior, which can reveal the network-level coordination of ras inhibitor function during reward processing, nor have studies examined the influence of social context on sexual risk-associated neural activity. In studying correlates of adolescent sexual behavior, it is critically important to distinguish between sexual behavior and sexual risk behavior. Research on adolescent sexual behavior has traditionally framed all sexual activity as risky and problematic, yet recent evidence indicates that sexual experience per se does not predict maladaptive outcomes—and may even be a marker of healthy social and psychological development (see Harden, 2014). In fact, recent conceptual models have emphasized the need for developmental neuroscience investigating sexual and romantic development as part of normative changes in social and affective circuitry (Suleiman et al., 2016). Evolutionary perspectives also highlight the normativity and centrality of sexual behavior during adolescence (Ellis et al., 2012). Although sexual behavior is a normative aspect of adolescent development, certain behaviors carry high levels of risk. Sexually active adolescents acquire half of all STIs (Center for Disease Control and Prevention, 2015) and an estimated 15% of sexually active adolescent girls aged 15–19 in the U.S. experience unintended pregnancy (Kost et al., 2010). Several specific types of behaviors are associated with increased risk and have been frequently studied in the adolescent sexual health literature, including a higher number of intercourse partners (Center for Disease Control and Prevention, 2015), early sexual debut (e.g., (Dixon-Mueller, 2008)), the use of alcohol at last intercourse (Kann, 2016), and the absence of condoms or birth control at last intercourse (Kann, 2016). Social reward, the experience arising from a positive social interaction (e.g., feeling accepted or being liked) is particularly salient during adolescence and activates neural reward and self-referential circuitry (Davey et al., 2010). Adolescents are also more likely to engage in risky behaviors during peer social interactions (Steinberg, 2008), which suggests that peer social reward is a relevant context for examining potential neural correlates or mechanisms of risky sexual behavior. As previous neuroimaging studies have examined aspects of regulatory, reward, and threat circuits in adolescent sexual risk-taking independent of social context, this study sought to examine neural function during the specific social context of social reward among adolescents engaging in higher-risk sexual behaviors. Using a social reward fMRI task, gene pool was hypothesized that adolescents who engage in riskier sexual behaviors would exhibit heightened activation and greater connectivity within social reward circuits in response to being liked by peers.