Age-related changes in heritability of cortical thickness also varied by brain region (see Fig. 5). Regions such as the primary motor and sensory cortices were significantly heritable in younger children but became progressively less so with time, such that genetic factors were not significant in young adults. Conversely, variation in regions such as the dorsal prefrontal and temporal regions was more environmentally driven in younger children, and became more strongly heritable with maturation (Lenroot et al. 2009).
