Fig 1.
Networks are extracted for each individual (upper panel) by extracting brain regions from the T1 image using FreeSurfer, and extracting structural and functional connectivity between these regions from preprocessed DWI and fMRI, respectively. Subsequently, integrated analysis of group differences in structural and functional connectivity is performed (lower panel). Group differences are visualized on a global level using bi-modal distribution plots, on an individual connection level using connectograms and on a mid-level using worm plots, where connections are grouped by location in the brain.
Table 1.
Subject demographics.
Fig 2.
Bi-modal network comparison plots.
Structure-function relationships are shown for the mean connectivity network of each group in (a) and (c), and the distribution of t-statistics in (b) and (d). (a) and (b) correspond to RSS, where in (a) blue represents the elderly group and red indicates the middle-aged group. (c) and (d) correspond to MGH, where in (c) blue represents the patients with schizophrenia and red represents controls. In the 2D structure-function histograms, magenta indicates overlap of the two groups. In the t-statistic histograms, green shows group differences, where positive values indicate elderly > middle-aged in RSS and schizophrenia > control in MGH.
Fig 3.
Connections in the (a) RSS and (b) MGH studies are grouped by location of region pairs. Groupings include subcortical (Sub), occipital (Occ), parietal (Par), temporal (Temp), frontal (Fro) and the cerebellum (Cb). Cb was not included in the RSS study. On the y-axis is the negative log of the p-value, multiplied by the sign of the corresponding t-statistic and scaled such that the line indicating p = 0.05 is at the same position for all plots.
Fig 4.
Connectograms of significant connections.
Red connections have significantly positive t-statistic values corrected for multiple testing, blue are negative (in the MGH schizophrenia > control, in the RSS old > young). Degree of significance is indicated by the opacity of the lines. Color saturation of regions shows the number of connections involving that region. For the RSS (a) DFA, (b) fPC and (c) fMT are shown. RSS DMC is not shown because there were too many significant connections to visualize. For the MGH (d) DFA (e) fPC and (f) fMT are shown. MGH DMC is not shown because there were no significant connections.