The developmental trajectory of grey matter follows an inverted parabolic curve, with cortical volume peaking, on average, around ages 12–14, followed by a decline in volume and thickness over adolescence (Giedd et al. 1999; Gogtay et al. 2004; Sowell et al. 2003). Widespread supratentorial diminutions are evident, but show temporal variance across regions (Wilke et al. 2007). Declines begin in the striatum and sensorimotor cortices (Jernigan and Tallal 1990; Jernigan et al. 1991; Sowell et al. 1999), progress rostrally to the frontal poles, then end with the dorsolateral prefrontal cortex (Gogtay et al. 2004; Sowell et al. 2002b), which is also late to myelinate (Paus et al. 1999). Longitudinal charting of brain volumetry (Giorgio et al. 2010) from 13–22 years of age reveals specific declines in medial parietal cortex, posterior temporal and middle frontal gyri, and the cerebellum in the right hemisphere, coinciding with previous studies showing these regions to develop late into adolescence (Giedd 2004; Gogtay et al. 2004; Sowell et al. 2002a, b). Examination of developmental changes in cortical thickness from 8–30 years of age indicates a similar
