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. 2015 Dec 23;113(2):E219–E228. doi: 10.1073/pnas.1508436113

Fig. 2.

Fig. 2.

Quantifying overlap between increased whole-brain connectivity in SCZ and independently defined association regions. (A) Using a priori defined, network-based parcellations (58, 101), we defined areal boundaries for the FPCN, and for the association cortex comprised of the FPCN, DMN, and VAN. (B) After down-sampling images to 10-mm voxels, to attenuate spatial correlations, 37% of areas showing elevated SCZ connectivity (Fig. 1H) overlapped with the FPCN (12.7% of total down-sampled gray matter voxels belong to the FPCN). In contrast, for the outside FPCN region, defined as all cortical gray matter not belonging to FPCN, there was far less overlap with regions of elevated SCZ connectivity (63%) than expected by chance (87.3%). (C) We repeated analyses using all association networks (FPCN, DMN, and VAN), again showing preferential colocalization of elevated SCZ connectivity with association regions. Again, the outside association region was defined as all cortical gray matter not belonging to the association region comprised of the FPCN, DMN, and VAN. An additional control analysis was computed using the combined sensory networks (SI Appendix, Fig. S11). (D) The significance above each bar represents the result from binomial tests computed for B and C and for sensory networks in SI Appendix, Fig. S11, comparing the expected percentage of significant voxels with the observed percentage of total significant voxels lying within each region (inside FPCN, outside FPCN, inside association, outside association, sensory networks). The percent spatial coverage plotted represents the total number of significant voxels in a region, divided by the total number of voxels for that region. The significance between bars marks difference between proportions, comparing spatial coverage within the FPCN (or association cortex) with spatial coverage outside, or comparing spatial coverage in association regions vs. spatial coverage in sensory regions. The dashed line marks the spatial coverage of all gray matter voxels by significant voxels (Fig. 1H). ***P < 0.001. Brain images are for visualization purposes only and have not been down-sampled. All reported statistics are computed on images that have been down-sampled to 10-mm voxels. Results remain unchanged without down-sampling (SI Appendix, Fig. S11).