More recently, another study (Lobier et al., 2018) investigated the role of long-range phase coupling in visuospatial attention processes, without a priori selection of frequency-bands or regions of interest. This study is particularly relevant from a methodological point of view since here phase coupling was assessed both using the weighted Phase Lag Index and the Phase Locking Value, the former to minimize the contribution of source leakage and the latter to exclude changes in phase lags without a change in coupling strength. Cortical activity was recorded with MEG from fourteen healthy participants performing a cued stimulus discrimination task. After a rightward or leftward cue presentation, subjects had to discriminate between two geometrical shapes with two different contrast conditions. The shapes were presented in the attended or non-attended hemifield. The results showed an increased inter-areal phase coupling in the high-alpha frequency band between visual, parietal, and frontal cortices. Interestingly, no major difference was observed between phase coupling assessed through wPLI or through PLV indicating that the observed findings cannot be attributed merely to source leakage nor to “systematic changes in phase
