Overall brain size changes little beyond early school age (Pfefferbaum et al. 1994), though the adolescent brain continues to undergo considerable maturation (Barnea-Goraly et al. 2005; Paus et al. 1999; Sowell et al. 1999). Changes in cortical volume occur alongside axonal growth and refinement of cortical connections (Huttenlocher and Dabholkar 1997; Yakovlev and Lecours 1967). Maturing neural circuitry, particularly in the prefrontal cortex, limbic system, and white matter association and projection fibers is linked with advancements in cognition and behavior, but also renders the adolescent brain vulnerable to unhealthy environmental influences.
