Adolescence marks a period of rapid development between childhood and adulthood involving complex social, biological, and psychological changes. The interactions of these multidimensional factors have considerable implications for adolescent development. Included in these alterations are substantial changes in the efficiency and specialization of the adolescent brain, which is accomplished through synaptic refinement and myelination 8. Synaptic refinement involves reductions in gray matter by eliminating unnecessary neural connections 9. During adolescence, this synaptic pruning occurs primarily in the prefrontal and temporal cortex 10 and in subcortical structures such as the striatum, thalamus, and nucleus accumbens 11, 12. The adolescent brain also undergoes increased myelination, which allows for improved integrity of white matter fiber tracts and efficiency of neural conductivity 13–16. Higher-order association areas appear to develop only after lower-order sensorimotor regions fully mature 17, with frontal lobes being the final areas of the brain to complete development. Along with these neuromaturational changes, it is suggested that increased myelination allows for smoother, more efficient communication between frontal-subcortical brain regions, allowing for better top-down cognitive control in adolescence 18.
