Theta-gamma coupling during a working memory task as compared to a simple vigilance task

► Theta-gamma coupling (TGC) was analyzed as measured by scalp EEG. ► A visuo-spatial 2-back task and a control task (vigilance task) were performed. ► An instantaneous phase method proposed by Cohen was used. ► TGC increased during the working memory task in the frontal area. ► Differences in TGC were observed at high-gamma frequency.