Our results revealed that the brain networks of BD patients have an altered functional connectivity pattern compared to healthy controls. Specifically, patients showed significantly decreased synchronization for the whole brain network in the alpha-band (Fig. 3). A previous EEG study reported that BD patients showed a generalized pattern of decreased alpha power at rest (Clementz et al., 1994). Whereas the alpha synchronization has been interpreted as idling signals, indicating an absence of information flow among brain areas (Pfurtscheller et al., 1996), recent studies suggest that alpha-wave synchronization reflects active inhibition that is required for efficient performance on cognitive or motor tasks (Herrmann et al., 2004; Sauseng et al., 2005). Because the SL measure in this study indicates how close a node is connected coincidently to other nodes of the network over time, our findings suggest incoherent or desynchronized spontaneous alpha-band activity during resting-state in BD. Furthermore, SL alpha deficits were most prominent in pairwise clusters comprising a subnetwork (Fig. 4) that included the frontal (F4), fronto-central (FC3 and FC4), central (Cz), and centro-parietal (CPz) regions. Decreased functional connectivity was greater
