Fig. 1: Method flowchart of the structural covariance gradient.

Vertex-wise cortical thickness was first extracted and down-sampled to 400 parcels from the Schaefer atlas⁵⁶. Structural covarying patterns were then estimated by using structural covariance of cortical thickness in typically developing (TD) controls, or early-onset schizophrenia (EOS) patients. After column-wise thresholding at 90%, the covariance matrix was then decomposed into 10 low-dimensional components by using the diffusion embedding method. Only the second component in TD, i.e., the second normative gradient, was related with the gradient axis derived from the human connectome project (HCP) data²⁸, and thus selected-out and used in further analyses.