Fig. 2.

Magnetization transfer (MT) mapping of intracortical myelination. (A) The schematic highlights estimation of MT on a contour (orange line) located at 70% of the cortical depth from the pial surface and another contour (green line) located 1 mm below the boundary between gray matter and white matter (yellow line). (C) These distances and others can be located approximately in the context of cytoarchitectonic lamina of human neocortex. (B) Baseline MT increases monotonically with distance from the pial surface, but (D) the age-related increase in MT (ΔMT) was greatest at 70% cortical depth. (E) The correlation between baseline MT and MBP gene expression was also strongest at 70% cortical depth. Boxes represent the medians and interquartile ranges over all 308 regions at each depth.