To assess the difference in lagged phase synchronization between pairs of ROIs for each frequency band across groups (AD vs. Controls, and APOE-4 carriers vs. noncarriers), eLORETA performed independent sample t-tests, thus obtaining t-statistic images of brain connectivity. For each analysis, 1026 tests were performed by eLORETA to compare all connections between 19 ROIs (171 connections) for each of the six frequency bands (171×6 = 1026). Furthermore, to correct for multiple comparisons, the eLORETA non-parametric randomization procedure based on “maximal statistic” was used [57], [58]. The omnibus null hypothesis was rejected if at least one t value (i.e., voxel tmax) was above the critical threshold tcrit for p = 0.05 determined by 5000 data randomizations. The eLORETA neuroimaging results of source-current density and functional connectivity are not adjusted for demographic data.
