Cortical and subcortical changes in typically developing preadolescent children.

There is evidence that abnormal cerebral development during childhood is a risk factor for various cognitive and psychiatric disorders. There is not, however, sufficient normative data available on large samples of typically developing children, especially within the narrow preadolescent age range. We analyzed high resolution MRI images from 126 normally developing children between ages 6 and 10 years. Age related differences in cortical thickness and in the volumes of major subcortical structures were assessed. Thinner cortices were observed in the occipital, parietal and somatosensory regions as well as in distinct regions of the temporal and frontal lobes with increasing age. Among the major subcortical structures analyzed in this study, only the thalamus showed increased volume with age after accounting for intracranial volume. Within the age range studied age-related cortical and subcortical differences were similar for boys and girls except for the right insula, where girls showed a slight increase in thickness with age. The findings reveal age-associated changes in brain anatomy, providing information about the trajectory of normal brain development during late childhood.