These matrices were derived as follows. We first extracted the subject-level intranetwork matrices from the seed-based ICN maps of each ROI set, using ROIs as nodes and mean connectivity z scores between ROI pairs Pifithrin-�� cost as the weights of the undirected edges (Watts and Strogatz, 1998). Edge weight for every node pair (e.g., nodes A and B) was defined at the subject level as the higher of two connectivity scores (A to B and B to A) for the A-B pair, where A to B connectivity was derived by (1) calculating the mean time series across all voxels

in node A, (2) determining the z scores for the connectivity of the node A time series to each voxel within node B, and (3) averaging the resulting z scores to create a single score. The B to A connectivity score was derived in like manner by reversing A and B in the procedure described above. This procedure made use of the extensive seed-based voxel-wise connectivity data generated for epicenter identification while producing

nearly identical node pair connectivity results, in pilot analyses, to those derived by calculating the correlation between the mean time series from nodes A and B. We then generated the group-level intranetwork adjacency matrix containing significant connections by performing a

one-sample t test on the group check details Rutecarpine of intranetwork matrices, stringently thresholded at p < 0.01, FDR corrected for multiple comparisons to avoid potentially spurious links introduced by low temporal resolution and hemodynamic blurring in the fMRI signal. The same process was performed for each of the five ROI sets, resulting in five thresholded intranetwork healthy functional intrinsic connectivity matrices (Figure 3). A lower statistical threshold of p < 0.05, FDR corrected for multiple comparisons, was used for the SD pattern to adjust for the fMRI signal loss characteristic of the temporal pole and orbitofrontal regions contained in this network, following previous approaches (Devlin et al., 2000 and Seeley et al., 2009). A single healthy transnetwork connectivity matrix, including all ROIs across the five atrophy patterns as one network, was constructed in like manner. In the group-level ICN matrices, the pairwise ROI connectivity t scores resulting from one-sample t test were used as edge weights.