To determine if PC1 effects were replicated at the vertex level, PCA was applied to vertex-wise data from IMAGEN-T1 and IMAGEN-T2. In this sensitivity analysis, PCA was applied to the vertex-wise data (163,842×2=327,684 vertices in total) at different smoothing kernels (FWHM=0, 5, 10, 15, 20, 25). Vertex-wise data were residualized using a linear model which modelled sex, age, ICV and dummy-coded site. Computations were performed on the Vermont Advanced Computing Core. The resulting vertex-wise standard loadings of PC1 were averaged for each region of the Desikan-Killiany atlas and compared against the original PC1 loadings from the parcellated data using Pearson’s correlation.
