, 2010 and Schlicht et al., 2010). The decomposition of amygdalostriatal interactions is an important direction for subsequent work exploring the development of emotion regulation. Future research should also attempt to better characterize the precise regulatory functions represented by VS responses during late childhood and early adolescence by, for example, contrasting patterns

of brain activity during intentional emotion regulation tasks with those where any moderation of affective responses is incidental (as was the case in our design). In contrast with two previous cross-sectional studies (Guyer et al., 2008 and Hare Gefitinib ic50 et al., 2008), we did not find evidence of significant increases in amygdala activity across expressions during adolescence. Even when examining each expression independently, only sad faces elicited significantly greater amygdala activity over time. However, our results appear consistent with the prior research when

one considers the age of our participants, who were just entering early adolescence, while the other studies examined amygdala responses throughout adolescence and into adulthood. In other words, upsurges Compound C in amygdala activity may be more extensive in middle adolescence, as suggested by inspecting the scatterplot from Hare et al. (2008) of amygdala reactivity to emotional expressions. Several analyses suggested that two emotions evince the most change in subcortical activity during the transition from childhood to adolescence: sadness and happiness. The enhanced response to sadness may be related to its increased salience in adolescence, or the emergence of more advanced 3-mercaptopyruvate sulfurtransferase understandings of sadness. Rates of depression begin to increase during early adolescence, particularly for girls (Cyranowski

et al., 2000 and Chaplin et al., 2009). Next to surprise, the ability to recognize sadness appears to be relatively late in developing—a recent behavioral study demonstrated that 10-year-olds were least accurate at recognizing sad facial expressions from multiple vantage points (compared to the recognition of anger, disgust, and fear), and most accurate at recognizing happy expressions (Lau et al., 2009). Future research should continue to explore why sadness and happiness may evidence more change at the neural and/or behavioral levels than most basic emotions during this period. Three other brain regions were identified in this study as demonstrating significant associations with increased resistance to peer pressure over time: temporal pole, dorsal striatum, and hippocampus. The temporal pole seems to play an important role in processing socioemotional information, including responding more to emotional than neutral facial expressions in adulthood (for a review, see Olson et al., 2007); our finding of longitudinal response increases in this region to emotional expressions versus neutral ones may pinpoint when this pattern first emerges.