PLoS ONE, Available online 17 August 2017
Early adolescence is a period of behavioural, emotional, and cognitive development. Identifying the normal brain development that underlies the behavioural and cognitive development can improve our understanding of developmental disorders. White matter consists of nerve fibers called axons that conduct impulses to different areas of the brain. Myelin gives white matter its colour because it surrounds the axons as insulation for impulse conduction. Magnetic resonance imaging (MRI) techniques have been used to investigate white matter development for over a decade. However, the techniques used to date are unable to determine the specific processes driving development. This study used a newer MRI technique to examine normal white and subcortical grey matter development from 8-13 years.
The results showed that brain developmental changes appear to be driven by changes in myelination and axon density, rather than by the axons becoming more coherent. This study helps understand what occurs in normal brain maturation, and suggests that these new MRI techniques may be to expand upon our knowledge of developmental disorders.