Figure 4.

The illustration of the putative morphological model of aging. This figure concludes our main findings as the following: (1) Gyral intrinsic curvature on the pial surface slightly increases with age. (2) Gyral intrinsic curvature on the white matter surface increases with age. (3) Sulcal intrinsic curvature on the pial surface decreases with age; sulcal width increases and sulcal depth decreases with age (4) Sulcal intrinsic curvature on the white matter surface increases with age. (1–4) Sulcal thickness declines more than gyral thickness (see the length of the red and blue arrows).