Alternating dynamics of segregation and integration in human EEG functional networks during working-memory task.

•The brain generates complex and transient coherent activity patterns which sustain network interactions among brain sites.•We investigated in a working memory task the origins of phenomena in high-density electroencephalography.•Pulses of precise network modes were observed in task trials.•In a first stage, networks elaborated information in separate groups of nodes.•In the second stage, networks favored configurations where information was integrated into small sets of core nodes.