FIG. 1.

k-core networks of controls and Alzheimer's disease (AD) subjects. Set of nodes present in the weighted k-cores of all 28 controls, k=18, (top left panel) and all 15 AD subjects (top right panel). The k-value was preselected to include at least half (i.e., the majority) of the detectable connected nodes per hemisphere (34×34). Results are presented over the whole brain. With disease progression, the left hemisphere of AD subjects loses consistency in its k-core assignments (false discovery rate [FDR] critical p-value=0.0015). Bottom panel shows p-values from the whole brain from a random effects regression between the k-cores (k=18) of controls and AD subjects (where controls were coded as 0 and AD subjects coded as 1) using age and sex as covariates and site as a random grouping variable; the significant connections that survived FDR were between the following cortical regions: the middle temporal and fusiform, inferior temporal and fusiform, pars triangularis and caudal middle frontal, precentral and caudal middle frontal, rostral middle frontal and pars opercularis, and superior parietal and lingual; also, a significant difference in the proportion of total fibers was detected in the following regions: fusiform, precuneus, rostral cingulate, and supra-marginal. Small black spheres show cortical areas where group differences were not detected.