Another limitation of this study can

Another limitation of this study can be seen in the relative small number of participants; this was due to significant logistical challenges in recruiting and retaining the participants, especially these from low socio-economic backgrounds. Under the circumstances, and given that the three groups showed no differences on any measure of cognitive, social, emotional and neural processing at the time of induction in our study (all p>0.1; see Habibi et al., 2014), we believe the results reported here provide an important contribution to the existing literature on music training and childhood development. Furthermore, given the longitudinal nature of our study, we believe that our findings are consistent with the notion of significant role of music training in child dna staining development; however, since allocation to training was not randomized, a causal relationship is only one possibility and other factors, such as motivation or predisposition towards music, could influence both group maintenance and changes in brain function.
Acknowledgments
We are also grateful to the Los Angeles Philharmonic, Youth Orchestra of Los Angeles, Heart of Los Angeles, Brotherhood Crusade and their Soccer for Success Program as well as the following elementary schools and community programs in the Los Angeles area: Vermont Avenue Elementary School, Saint Vincent School and Macarthur Park Recreation Center. This research was funded in part by an anonymous donor and by the USC’s Brain & Creativity Institute Research Fund.
Introduction One of the most salient characteristics for social information processing is reading emotions from faces: multiple types of information, such as gender, age, emotional state and trustworthiness are processed within several hundreds of milliseconds and provide crucial information for social interactions (Adolphs, 2002; Fusar-Poli et al., 2009; Grossmann and Johnson, 2007). Prior research has shown that the fusiform cortex and the amygdala are important brain regions involved in this process (Fusar-Poli et al., 2009), where the amygdala is often interpreted as a region involved in detecting the valence and intensity of expressed emotions (Costafreda et al., 2008; Whalen et al., 2009). Developmental neuroimaging studies reported that activity in monocytes network is restructured in mid-adolescence (Casey et al., 2011), such that intensified emotion-processing makes the amygdala sensitive to reading emotions from faces of unknown others (Scherf et al., 2013). This is in line with several studies reporting that the amygdala shows stronger activity to emotional face processing in mid-adolescence compared to child- and adulthood (Guyer et al., 2008; Hare et al., 2008; Pfeifer et al., 2011; Somerville et al., 2011). Research indicated that there are pronounced differences in amygdala activation between adults and adolescents with and without depression and anxiety disorders (also known as internalizing disorders). Several reports have shown that amygdala responsiveness is higher in healthy individuals who report high levels of depression or anxiety symptoms without being diagnosed with an internalizing disorder and in individuals diagnosed with an internalizing disorder (Monk et al., 2008a,b; Roberson-Nay et al., 2006; Somerville et al., 2004; Thomas et al., 2001; van den Bulk et al., 2014). These findings suggest that individuals with internalizing disorders demonstrate hypervigilant affective processing, which can be measured via individual differences in amygdala response to emotional faces. Individuals who have a history of childhood maltreatment, such as childhood sexual abuse (CSA), also show increased patterns of amygdala activation (Garrett et al., 2012; Hart and Rubia, 2012). However, studies examining the neurobiological mechanisms of childhood maltreatment are scarce and many of the studies including adolescents who experienced childhood maltreatment, do not focus on CSA. There are only a few studies that investigated amygdala activation in adolescents with CSA-related PTSD. Research by Cisler et al. (2015) for example showed that adolescent girls who experienced physical or sexual assault and who were referred for trauma-focused cognitive behavioural therapy reacted differently to treatment based on their pre-treatment level of amygdala activation in response to threatening emotional faces: adolescents with a stronger amygdala response to emotional faces pre-treatment, showed les symptom reduction.