Figure 1.

The procedures employed for the functional connectivity variability analysis.(A) The three types of functional connectivity: FC, pFC, and pseudo-FC. Functional connectivity was defined by Pearson correlation coefficient (FC) and partial correlation (pFC). Pseudo-functional connectivity (pseudo-FC) was defined as the difference between FC and pFC, i.e., the edges where FC exists but pFC does not. Pseudo-FC can be derived with polysynaptic connections or common feed-forward projections without direct interactions between two regions. (B) The analyses used in this study were as follows: (1) the acquisition of resting state fMRI data at eight different time points during a day and DTI data, (2) calculation of three types of functional connectivity (i.e., FC, pFC, and pseudo-FC) and structural connectivity (i.e., log-transformed fiber counts), (3) correlation analyses between intra-class correlations (ICCs, stability) of the functional connectivity and structural connectivity according to edge properties (fiber counts and lengths), edge types (intra-hemispheric and inter-hemispheric homologous and heterologous edges), and topological edge types under rich club architecture, and (4) evaluations of the multivariate edge involvement pattern similarity under the rich club architecture. The multivariate pattern similarity was evaluated by calculating the average similarities of the connectivity matrices within subnetworks of the rich club nodes across the different time points within a day. Note that variability was evaluated with similarity measures (1–similarity).