A comprehensive study of whole-brain functional connectivity in children and young adults.

Over the past decade, examination of functional connectivity using functional magnetic resonance imaging has become an important tool to investigate functional changes in patient populations, healthy aging, and recently also child development. Most prior developmental studies focused on functional connectivity between brain regions important for cognitive or emotional control and the so-called "default-mode network." In the present study, we investigated whole-brain functional connectivity in children (11-13 years; N = 19) and young adults (19-25 years; N = 29), without a priori restrictions to specific regions. We found similar patterns of functionally connected regions in children and young adults, but there were differences in the size of functionally connected regions (i.e., the number of voxels), as well as in the strength of functional connectivity (i.e., the correlation value) between brain regions. This indicates that functional connectivity continues to change during adolescence. Developmental differences were found across the whole brain, but the effects differed for functional connectivity patterns associated with higher cognitive or emotional functions and functional connectivity patterns associated with basic visual and sensorimotor functions. Finally, we showed that the majority of functional connectivity differences could not be explained on the basis of gray matter density alone.