Although it has been established that many of the

Although it has been established that many of the neural systems involved in romantic love and sex undergo significant structural, connectivity, and functional transformation during puberty, little is known about how this intersects with a normative romantic and sexual developmental trajectory. Integrating what is known about the neural underpinnings of romantic love and sexual desire/arousal in adults with the literature on pubertal neurodevelopment points to some intriguing questions. While it is beyond the scope of this paper to summarize this body of literature, adolescent neurodevelopmental models have clearly demonstrated significant sex-specific restructuring of the rac protein during puberty (Dennison et al., 2013; Giedd and Denker, 2015). Despite sex differences in these trajectories, all adolescent brains are sensitized to reward learning (Galván, 2013). By activating dopamine-rich, reward processing and motivational systems, both romantic love and sex are goal-oriented motivations accompanied by strong emotional responses (Aron et al., 2005; Fisher et al., 2010). Beginning with puberty, the developmental transitions in brain networks involved in motivation, reward, and social-emotional processing likely create a unique inflection point for romantic love and sexual arousal to be experienced as positive rewards. Both love and sexual desire are dopamenergically-mediated motivation states that can globally affect cognition (Diamond and Dickenson, 2012). Given the developmental transitions that occur during adolescence related to emotional processing and cognitive control, it has been proposed that adolescence is an opportune time to explore the cognitions and emotions associated with romantic relationships (Collins, 2003). These new motivational states significantly increase in salience at the same time that youth develop an increased capacity for self-regulation of other appetitive behaviors (Fortenberry, 2013). It therefore makes sense that physical maturation is accompanied by increased neural plasticity and a heightened motivation to seek out a range of highly arousing, slightly scary, highly rewarding, novel experiences, and that increases in sensation seeking make adolescents more likely to find these high-intensity experiences, such as having a first crush or engaging in a first kiss, enjoyable (Spielberg et al., 2014). The co-release of dopamine and oxytocin associated with repeated interactions with a specific partner contributes to additional reward-driven learning about romantic behaviors. Once a young person has a crush and begins to build a relationship with someone, they develop a conditioned partner response in which the dopaminergic reward is expected and experienced greatest with that specific bonded partner (Love 2013; Ortigue et al., 2010). As with all learning, partner preference takes time, as well as repeated experience, to develop. Once this partner-specific response has been established, engaging in arousing, novel activities creates enhanced experiences of relationship satisfaction among couples (Aron et al., 2000). Because of the neural development occurring with puberty, a partner-specific response in early romantic relationships, when both the emotional and physical intimacies are novel, makes them particularly exciting, rewarding, and satisfying. In order to engage in romantic and sexual relationships successfully, adolescents need to want, like, approach, and learn from the high-stakes activities of asking someone out on a first date, falling in love, experiencing a broken heart, and trying again. Romantic love involves increased activation in dopamine-rich subcortical regions associated with processing emotion, rewards, and motivation; in the higher-order cortical brain regions associated with social cognition and self-representation; and decreased activation in the amygdala (Ortigue et al., 2010). Although sexual desire/arousal and love involve many overlapping areas of activation, particularly in the subcortical regions, there are also distinct areas of activation. For example, romantic love, both while someone is actively in love and after they have experienced rejection from a break-up, but not sexual arousal, involves ventral tegmental activation (generally associated with pleasure, focused attention, and motivation to pursue rewards), whereas sexual arousal, but not love, involves ventral striatal activation (associated with motivation and predictive reward value) (Fisher et al., 2010; Diamond and Dickenson, 2012). Due to limitations in developing tasks appropriate for the scanner, neuroimaging research has not successfully distinguished sexual desire—a cognitively-mediated motivation state to pursue sexual activity—from sexual arousal—a physiological state of sexual readiness (Diamond and Dickenson, 2012). Most laboratory paradigms use sexual stimuli of strangers rather than loved ones, and thus likely better represent arousal than desire, but this remains unclear. Research on the developmental trajectory of love in the human brain is incredibly limited. Puberty offers a unique developmental inflection point when romantic love emerges. Uncovering the neural developmental trajectories that contribute to the emergence of romantic love and sexual arousal could help to expand our understanding of these motivational states. In addition, research that helps to unpack how neurodevelopmental transitions occurring at puberty interact with early experiences of desire, romantic love, and sex would greatly increase our understanding of how the inflection point of puberty creates a unique developmental window for learning about these complex social activities.