Maturational trajectories of pericortical contrast in typical brain development

Abstract

In the last few years, a significant amount of work has aimed to characterize maturational trajectories of cortical development. The role of pericortical microstructure putatively characterized as the gray-white matter contrast (GWC) at the pericortical gray-white matter boundary and its relationship to more traditional morphological measures of cortical morphometry has emerged as a means to examine finer grained neuroanatomical underpinnings of cortical changes. In this work, we characterize the GWC developmental trajectories in a representative sample (n = 394) of children and adolescents (~4 to ~22 years of age), with repeated scans (1-3 scans per subject, total scans n = 819). We tested whether linear, quadratic, or cubic trajectories of contrast development best described changes in GWC. A best-fit model was identified vertex-wise across the whole cortex via the Akaike Information Criterion (AIC). GWC across nearly the whole brain was found to significantly change with age. Cubic trajectories were likeliest for 63% of vertices, quadratic trajectories were likeliest for 20% of vertices, and linear trajectories were likeliest for 16% of vertices. A main effect of sex was observed in some regions, where males had a higher GWC than females. However, no sex by age interactions were found on GWC. In summary, our results suggest a progressive decrease in GWC at the pericortical boundary throughout childhood and adolescence. This work contributes to efforts seeking to characterize typical, healthy brain development and, by extension, can help elucidate aberrant developmental trajectories.

Keywords: Adolescence; Brain development; Childhood; Cortical contrast; Gray-white contrast; Structural MRI.

Fig. 1.

Calculation of GWC, Example showing the placement of the 25% distance surfaces in the gray matter and superficial white matter.

Fig. 2.. Map of vertex-wise Model Winners of GWC trajectories, 5% FDR.

Prevailing model based on AIC denoted: Blue = Linear, Green = Quadratic, Purple = Cubic.

Fig. 3.. Cubic age trajectory of whole-brain, mean GWC.

Black curve is derived from the model prediction on the full sample. The blue and red curves represent predictions from modeling performed on the male- and female-only subsets of the data, respectively.

Fig. 4.

A. Qualitative overview of developmental trajectories of GWC, on the left lateral cortical surface. Black curves are derived from the model prediction on the full sample. The blue and red curves represent predictions from modeling performed on male- and female-only subsets of the data, respectively, and better reflect the true trajectories of males and females in our data. Even if these are not perfectly parallel to the global trajectory, there is no statistically significant ‘sex by age’ interaction. B. Qualitative overview of developmental trajectories of GWC, on the left medial cortical surface. Black curves are derived from the model prediction on the full sample. The blue and red curves represent predictions from modeling performed on male- and female-only subsets of the data, respectively, and better reflect the true trajectories of males and females in our data. Even if these are not perfectly parallel to the global trajectory, there is no statistically significant ‘sex by age’ interaction.

Fig. 4.

A. Qualitative overview of developmental trajectories of GWC, on the left lateral cortical surface. Black curves are derived from the model prediction on the full sample. The blue and red curves represent predictions from modeling performed on male- and female-only subsets of the data, respectively, and better reflect the true trajectories of males and females in our data. Even if these are not perfectly parallel to the global trajectory, there is no statistically significant ‘sex by age’ interaction. B. Qualitative overview of developmental trajectories of GWC, on the left medial cortical surface. Black curves are derived from the model prediction on the full sample. The blue and red curves represent predictions from modeling performed on male- and female-only subsets of the data, respectively, and better reflect the true trajectories of males and females in our data. Even if these are not perfectly parallel to the global trajectory, there is no statistically significant ‘sex by age’ interaction.

Fig. 5.. Estimated trajectories of GWC maturation across various representative regions exhibiting a significant sex effect on GWC.

Black curves are derived from the model prediction on the full sample. The blue and red curves represent predictions from modeling performed on male- and female-only subsets of the data, respectively, and better reflect the true trajectories of males and females in our data. Even if these are not perfectly parallel to the global trajectory, there is no statistically significant ‘sex by age’ interaction.