The longitudinal data of the NCANDA Release (NCANDA_PUBLIC_2Y_STRUCTURAL_V02), which was made available through the Scalable Informatics for Biomedical Imaging Studies (Muller-Oehring et al. 2017; Nichols and Pohl 2015; Pfefferbaum et al. 2016; Pohl et al. 2016; Rohlfing et al. 2014) (sibis.sri.com), included 226 adolescents (108 male; 118 female) aged 12 to 21 years. These participants were recruited by the University of Pittsburgh (N=90; site P) and the Oregon Health and Sciences University (N=136; site O), and their demographic information is summarized in Table 1. They met no-to-low alcohol and drug use criteria (Brown et al. 2015), urine screening on the day of scanning confirmed the absence of recreational drug use, and were scanned on Siemens MRI systems as recommended for myelin mapping (Glasser et al. 2014). 32 participants were ambidextrous (Edinburgh handedness questionnaire (Oldfield 1971)) and of the remaining 194 adolescents Grooved Pegboard Test were administrated separately for each hand (Lafayette-Instrument 2002). All participants underwent an informed consent process with a research associate trained in human subject research protocols. Adult participants provided written informed consent as did the parents of
