@article {Vanderwal828137, author = {Tamara Vanderwal and Jeffrey Eilbott and Clare Kelly and Todd S. Woodward and Michael P. Milham and F. Xavier Castellanos}, title = {Stability and similarity of the pediatric connectome as developmental outcomes}, elocation-id = {828137}, year = {2019}, doi = {10.1101/828137}, publisher = {Cold Spring Harbor Laboratory}, abstract = {Patterns of functional connectivity are unique at the individual level, enabling test-retest matching algorithms to identify a subject from among a group using only their functional connectome. Recent findings show that accuracies of these algorithms in children increase with age. Relatedly, the persistence of functional connectivity (FC) patterns across tasks and rest also increases with age. This study investigated the hypothesis that within-subject stability and between-subject similarity of the whole-brain pediatric connectome are developmentally relevant outcomes. Using data from 210 help-seeking children and adolescents, ages 6-21 years (Healthy Brain Network Biobank), we computed whole-brain FC matrices for each participant during two different movies (MovieDM and MovieTP) and two runs of task-free rest (all from a single scan session) and fed these matrices to a test-retest matching algorithm. We replicated the finding that matching accuracies for children are low (18-44\%) relative to previous work in adults and found that cross-state and cross-movie accuracies for children were the lowest. Next, we calculated three measures of connectome stability for each subject: cross-rest (Rest1-Rest2), cross-state (Rest1-MovieDM), and cross-movie (MovieDM-MovieTP), and three measures of within-state between-subject connectome similarity for Rest1, MovieDM, and MovieTP. We show that all six measures of stability and similarity are correlated, but that these measures are not related to age. A principal component analysis of these measures yielded two components that were used to test for brain-behavior correlations with IQ, general psychopathology, and a social skills measure (n=119). The first component was significantly correlated with the social skills measure (r=-0.27, p=0.003) and overall psychiatric scores (r=-0.239, p=0.009). Post hoc correlations showed that cross-rest stability was correlated with both social skills (p=0.0007) and general psychopathology (p=0.001). Connectome similarity during MovieDM was also correlated with social skills (p=0.0026). These findings suggest that the stability and similarity of the whole-brain connectome relate to overall brain development, and in particular, to those regions that support social cognition. We infer that the development of the functional connectome simultaneously achieves patterns of FC that are distinct at the individual subject level, that are shared across individuals, and that are persistent across states and across runs{\textemdash}features which presumably combine to optimize neural processing during development. Future longitudinal work could reveal the developmental trajectories of stability and similarity of the connectome.Highlights- Identification algorithms yielded low accuracies in this developmental sample.- Individual differences in FC were not as persistent across states or movies.- Connectome within-subject stability and between-subject similarity were interrelated.- Stability during rest and similarity during a movie correlate with social skills scores.}, URL = {https://www.biorxiv.org/content/early/2019/11/01/828137}, eprint = {https://www.biorxiv.org/content/early/2019/11/01/828137.full.pdf}, journal = {bioRxiv} }