There was carried out a correlation analysis for the frequency of the background impulse activity of the brain stem monoaminergic neurons and the spectral power of electroencephalogram frequency components in a wakeful cat. The frequency of the background impulse activity in the studied neurons was found to be reliably (p < 0.05) correlated with all basic electroencephalogram rhythms. Among the statistically significant correlations, there were most often observed the positive ones between the background impulse activity of the ventral tegmentum dopaminergic neurons and the locus coeruleus noradrenergic neurons, on the one hand, and the power spectral density of alpha-rhythm, on the other hand (40.3% and 48.0% respectively). Besides, 47.7% of the raphe nuclei serotoninergic neurons under study showed positive correlation between their impulse activity and the spectral power density of beta-rhythm. The results obtained let us assume the possibility of taking specific EEG patterns as markers of activity for the basic cerebral monoaminergic systems.