TY - JOUR T1 - Synergistic effects of age on patterns of white and gray matter volume across childhood and adolescence JF - eneuro JO - eneuro DO - 10.1523/ENEURO.0003-15.2015 SP - ENEURO.0003-15.2015 AU - Signe Bray AU - Mark Krongold AU - Cassandra Cooper AU - Catherine Lebel Y1 - 2015/07/01 UR - http://www.eneuro.org/content/early/2015/07/01/ENEURO.0003-15.2015.abstract N2 - The human brain develops with a non-linear contraction of gray matter across late childhood and adolescence, and a concomitant increase in white matter volume. Across the adult population, properties of cortical gray matter co-vary within networks that may represent organizational units for development and degeneration. Although gray matter covariance may be strongest within structurally connected networks, the relationship to volume changes in white matter remains poorly characterized. In the present study we examined age-related trends in white and gray matter volume using T1-weighted MR images from 360 human participants from the NIH MRI study of Normal Brain Development. Images were processed through a voxel-based morphometry pipeline. Linear effects of age on white and gray matter volume were modeled within four age bins, spanning 4-18 years, each including 90 participants (45 male). White and gray matter age-slope maps were separately entered into k-means clustering, to identify regions with similar age-related variability across the four age bins. Four white matter clusters were identified, each with a dominant direction of underlying fibers: anterior-posterior, left-right, and two clusters with superior-inferior directions. Corresponding, spatially proximal, gray matter clusters encompassed largely cerebellar, fronto-insular, posterior and sensorimotor regions, respectively. Pairs of gray and white matter clusters followed parallel slope trajectories, with white matter changes generally positive from 8 years onward (indicating volume increases) and gray matter negative (decreases). As developmental disorders likely target networks rather than individual regions, characterizing typical coordination of white and gray matter development can provide a normative benchmark for understanding atypical development.Significance statement: The structure of the brain changes across late childhood and adolescence: gray matter volume decreases and white matter volume increases. Gray matter changes occur within networks that may be targets for neurodegenerative, developmental and psychiatric disorders. This study demonstrates that changes in white matter volume are also coordinated across regions, and that changes in these clusters parallel corresponding gray matter clusters. While gray matter clusters show a posterior to anterior organization, we observe here that white matter volume groups into regions with similar fiber orientation. This work adds to our understanding of typical gray and white matter development, which ultimately can help to understand how the brain may be developing abnormally in neurodevelopmental disorders. ER -