Further MRI evidence of late brain maturation: Limbic volume increases andchanging asymmetries during childhood and adolescence

In this article, we extend earlier findings of age-related changes in brain morphology on magnetic resonance images to include measurements of the mes ial temporal lobe as well as asymmetry measures in regional cortical and su bcortical structures. The earlier sample was increased to include 57 childr en and young adults aged 8 to 35 years. The participants were studied using quantitative image analytic techniques. Estimated volumes of limbic and an terior diencephalic structures increased significantly with age; although i nferior lateral cortex, superior cortex, caudate nuclei, thalamus, and lent icular nuclei all decreased significantly with age. Of the 7 regions measur ed, only the lenticular nucleus and anterior diencephalon showed significan t changes in asymmetry with increasing age. It is hypothesized that some of these changes may be related to the changing levels of gonadal steroid hor mones known to occur during this age range. They may also have important im plications for the study of late developing higher cognitive functions and the loss of behavioral plasticity.