[On the road to understanding the phenomena of pharmacological electroencephalography]

In animal studies (outbred albino rats with different types of conflict behaviour, cottontail rats, inbred mice) it was established that the anxiolytic effects of benzodiazepine and atypical tranquilizers including buspirone are associated only with EEG theta-rhythm slowing. At the same time, anxiogenic drugs caused an increase in frequency of the theta-activity and (in large doses) increase of low-frequency spindles. These EEG-changes are close to the patterns of EEG induced by stress. These results suggest that increase in the beta-activity, especially, owing to high-frequency spindles, which has been reported to be a common feature of all tranquilizers, might be connected with adaptive mechanisms of the brain preventing from lesions by psychotropic drugs. It is possible that some abnormal EEG activity of epileptic humans and animals (spike-slow wave, spindles) also is a reflection of these adaptive mechanisms of the brain.