Sex differences in brain maturation during childhood and adolescence

Brain development during childhood and adolescence is characterized by both progressive myelination and regressive pruning processes. However, sex dif ferences in brain maturation remain poorly understood. Magnetic resonance i maging was used to examine the relationships between age and sex with cereb ral gray and white matter volumes and corpus callosal areas in 118 healthy children and adolescents (61 males and 57 females), aged 6-17 years. Gender groups were similar on measures of age, handedness, socioeconomic status a nd Full Scale IQ. Significant age-related reductions in cerebral gray and i ncreases in white matter volumes and corpus callosal areas were evident, wh ile intracranial and cerebral volumes did not change significantly. Signifi cant sex by age interactions were seen for cerebral gray and white matter v olumes and corpus callosal areas. Specifically, males had more prominent ag e-related gray matter decreases and whits matter volume and corpus callosal area increases compared with females. While these data are from a cross-se ctional sample and need to be replicated in a longitudinal study, the findi ngs suggest that there are age-related sex differences in brain maturationa l processes. The study of ega-related sex differences in cerebral pruning a nd myelination may aid in understanding the mechanism of several developmen tal neuropsychiatric disorders.