Fig. 1.

Flowchart for the construction of the white matter structural network. (1) Register the T1-weighted image (a) to the non-diffusion image (b) in DTI native space for each subject. (2) Register the resultant T1 image to the ICBM152 T1 template (d) in the MNI space, resulting in a nonlinear transformation (T). (3) Apply the inverse transformation (T^− 1) to the AAL90 template (e) in the MNI space, resulting in a subject-specific parcellation (f) in the DTI native space. (4) For each region, estimate the connectivity probability with other brain regions by using probabilistic tractography (c). In c, the yellow–red colors represent the connected probability from the right superior frontal gyrus (marked as green) to the other regions. (5) Construct the weighted network (g) for each subject by computing the connection probability between each pair of regions. (6) Threshold the individual matrix under a range of sparsity from 5% to 25% with an interval of 0.5%: sparsity = 25% (h); sparsity = 15% (i); sparsity = 5% (j). The visualization of the sparse networks was represented at lateral view.