The Concurrence of Cortical Surface Area Expansion and White Matter Myelination in Human Brain Development

Abstract

The human brain undergoes dramatic structural changes during childhood that co-occur with behavioral development. These age-related changes are documented for the brain’s gray matter and white matter. However, their interrelation is largely unknown. In this study, we investigated age-related effects in cortical thickness (CT) and in cortical surface area (SA) as parts of the gray matter volume as well as age effects in T1 relaxation times in the white matter. Data from N = 170 children between the ages of 3 and 7 years contributed to the sample. We found a high spatial overlap of age-related correlations between SA and T1 relaxation times of the corresponding white matter connections, but no such relation between SA and CT. These results indicate that during childhood the developmental expansion of the cortical surface goes hand-in-hand with age-related increase of white matter fiber connections terminating in the cortical surface.

Charting shared developmental trajectories of cortical thickness and structural connectivity in childhood and adolescence

“…Cafiero et al recently demonstrated that streamlines passing through regions of myelinating white matter in early childhood terminate within large swathes of the developing cortex (Cafiero et al, 2019). As the cortical and connectivity components were linked by a shared timecourse, this likely reflects a combination of developmental processes occurring simultaneously within the brain.…”

“…Our use of supervised NMF to derive a corresponding set of con- from specific cortical gyri (Jeon, Mishra, Ouyang, Chen, & Huang, 2015) or connections between cortical areas that displaying significant age-related changes in surface area in childhood (Cafiero, Brauer, Anwander, & Friederici, 2019). A strength of our approach is that we used a data-driven method to select important connections based on their covariation with each cortical component.…”

“…Other studies have employed different methods to study concomitant changes across both tissue compartments. These approaches include inspection and comparison of white matter properties directly subjacent to different cortical regions (Croteau-Chonka et al, 2016), or examination of white matter tracts from specific cortical gyri (Jeon, Mishra, Ouyang, Chen, & Huang, 2015) or connections between cortical areas that displaying significant age-related changes in surface area in childhood (Cafiero, Brauer, Anwander, & Friederici, 2019). A strength of our approach is that we used a data-driven method to select important connections based on their covariation with each cortical component.…”

“…As the cortical and connectivity components were linked by a shared timecourse, this likely reflects a combination of developmental processes occurring simultaneously within the brain. Cafiero et al recently demonstrated that streamlines passing through regions of myelinating white matter in early childhood terminate within large swathes of the developing cortex (Cafiero et al, 2019). We chose FA to define white matter connectivity strength, a partial proxy for white matter myelination in the developing brain (Lebel & Beaulieu, 2011).…”

Charting shared developmental trajectories of cortical thickness and structural connectivity in childhood and adolescence

“…Other studies have employed different methods to study concomitant changes across both tissue compartments. These approaches include inspection and comparison of white matter properties directly subjacent to different cortical regions (Croteau-Chonka et al 2016), or examination of white matter tracts from specific cortical gyri (Jeon et al 2015) or connections between cortical areas that displaying significant age-related changes in surface area in childhood (Cafiero et al 2019). A strength of our approach is that we used a data-driven method to select important connections based on their co-variation with each cortical component.…”