Fig. 4.

(a) Longitudinal inner cortical surfaces of the left hemisphere of a representative infant from 1 to 24 months of age, color-coded by the mean curvatures, as well as their within-subject mean cortical surface (color-coded by the average values of mean curvatures of all time points) computed based on the cortical correspondences established by within-subject groupwise surface registration. (b) Longitudinal spherical surfaces of the left hemisphere of the infant after within-subject groupwise registration, color-coded again by the mean curvatures, and their average values of mean curvature of all time points. Red colors indicate sulci, and blue colors indicate gyri. Here the mean curvature reflects the fine-scale geometry of the cortical folding. As we can see, the within-subject mean cortical folding is very sharp and contains very detailed information of folding patterns.