[Relation between fast EEG rhythms and contingent negative variation]

The experiments were done to investigate the relationships between activation level and contingent negative variation (CNV). Two groups of subjects, differing in their level of cortical arousal, were recorded with eyes open (OE, N = 17) or eyes closed (CE, N = 40). Beta activity, CNV, electro-oculogram, reaction time and heart rate were studied. In the CE group, beta activity and CNV were not significantly correlated. In the OE group, CNV was slightly extended with a higher amplitude and a higher post-imperative negativity when beta activity was higher; heart rate was also significantly correlated with beta activity in this group. The results are discussed as a function of the existence of two neurophysiological mechanisms of generation and regulation of CNV.