Phase Synchronization Analysis of EEG during Attentional Blink

The attentional blink (AB) phenomenon occurs when perceivers must report two targets embedded in a sequence of distracters; if the first target precedes the second by 200-600 msec, the second one is often missed. We investigated AB by measuring dynamic cross-lag phase synchronization for 565 electrode pairs in 40-Hz-range EEG. Phase synchrony, on average, was higher in experimental conditions, where two targets are reported, than in control conditions, where only the second target is reported. The effect occurred in electrode pairs covering the whole head. Timing of the synchrony was crucial: Brief episodes of enhanced synchrony occurred 100-500 msec before expected target onset in AB conditions where the second target was correctly reported. These results show that intrinsic brain dynamics produce anticipatory synchronization in transient assemblies of cortical areas. Enhanced levels of anticipatory synchronization occur in response to the demands of the task in conditions where the system's limited capacity is under strain.