Figure 2.

Schematic overview of formation of individual structural brain networks. For each individual dataset, a structural brain network was constructed. First, for each dataset (a) from the AAL template consisting of 108 unique brain regions (54 each hemisphere), two regions, i and j, were selected (b). From the total collection of reconstructed white matter tracts (based on the DTI data), the white matter fibers interconnecting region i and region j were selected by selecting those tracts that touched both region i and region j. If this selection procedure revealed fibers between i and j (c), node i and node j in the brain network were interconnected by a connection. Furthermore, the weight w_ij of the connection between node i and j was selected as the MTR value along the selected fibers, reflecting the level of myelination of the selected tract (d), and w_ij was included in cell c_ij of the weighted connectivity matrix M. If no tract was found between region i and j, no connection was included in graph G, resulting in c_ij value of 0 in M. These steps were repeated for all regions i and j in the AAL template (e), resulting in a filled weighted connectivity matrix M, representing a weighted undirected graph G (f). Next, from the resulting brain network overall organizational characteristics (g) and node-specific organizational characteristics (h) (see supplemental materials and Fig. 1) were computed and compared between patients and healthy controls (i).