Resting anxiety increases EEG delta–beta correlation: Relationships with the Reinforcement Sensitivity Theory Personality traits

Research has shown that the coupling between slow and fast EEG frequency oscillations reflects cortico-subcortical interaction. Specifically, the between-subject delta-beta amplitude-amplitude correlation is found to increase in some hypothetically anxiogenic conditions. We tested whether cortical-subcortical coupling would increase as a function of decreased delta (theta) or higher beta (gamma) activity. EEG recording was obtained from a group of 59 students during a resting anxiogenic situation (Anxiety) and from another group of 66 during a relaxation situation (Relaxation). Participants filled out the State Anxiety and the Reinforcement Sensitivity Theory Personality Questionnaire. Between-subjects cross-frequency correlations were calculated between power values in the delta (theta) and beta (gamma) frequency bands and compared between Anxiety and Relaxation groups. A significant positive between-subject delta-beta correlation was observed in the resting Anxiety, and this association was significantly higher than that observed in the Relaxation group. In the Anxiety, but not Relaxation group, we observed a delta-beta coupling for the low delta activity. In the Anxiety group, BIS trait was significantly associated with higher strength of within-subject delta-beta coupling, while in the Relaxation group BIS was positively associated with delta-theta coupling. Interesting, in both resting Anxiety and Relaxation groups, BAS-GDP was positively associated with higher delta-gamma coupling.