Covariation of EEG synchronization and emotional state as modified by anxiolytics.

The relationships between subjective estimation of emotional state and synchronization patterns in cortical emotional systems were investigated. The emotional state varied between groups using diazepam, buspirone, and placebo. The University of Wales Institute of Science and Technology Mood Adjective Checklist was used for the assessment of emotional state in the drug condition, yielding three estimates of emotional state: Energetic Arousal, Tension Arousal, and Hedonic Tone. These measures were correlated with the Synchronization Likelihood index of the resting EEG. Increased affective valence and arousal were related to an increased level of synchronization between frontal and right temporoparietal emotional areas. Two identified centers of synchronization, localized in the temporal and centroparietal regions, appeared to be functionally distinct. Stable relationships between subjective emotional state measures and cortical EEG synchronization patterns were confirmed, especially for the valence and energetic arousal estimation. A higher synchronization is associated with increased emotional valence and arousal, and this can thus be seen as a neural correlate of emotional experiences.