UC San Diego

In this article, we extend earlier findings of age-related changes in brain morphology on magnetic resonance images to include measurements of the mesial temporal lobe as well as asymmetry measures in regional cortical and subcortical structures. The earlier sample was increased to include 57 children and young adults aged 8 to 35 years. The participants were studied using quantitative image analytic techniques. Estimated volumes of limbic and anterior diencephalic structures increased significantly with age; although inferior lateral cortex, superior cortex, caudate nuclei, thalamus, and lenticular nuclei all decreased significantly with age. Of the 7 regions measured, only the lenticular nucleus and anterior diencephalon showed significant changes in asymmetry with increasing age. It is hypothesized that some of these changes may he related to the changing levels of gonadal steroid hormones known to occur during this age range. They may also have important implications for the study of late developing higher cognitive functions and the loss of behavioral plasticity.