The timing of theta phase synchronization accords with vigilant attention.

Vigilant attention plays an important role in some industries and everyday life. However, its mechanism relating to phase synchronization of cortical oscillations is still unknown, which hinders the development of predicting and preventing vigilant attentional deficit. This study utilized psychomotor vigilance test (PVT) to elicit vigilance decrement. High and low levels of vigilant attention were represented by short and long reaction time, respectively. Electroencephalogram (EEG) was collected and phase synchronization between prefrontal and parietal cortices was analyzed by using debiased weighted phase lag index (dWPLI). The result suggests that vigilant attention of high level has earlier timing of theta (4-8Hz) phase synchronization, compared with that of low level. We concluded that phase synchronization may relate closely with the variation of vigilant attention.