The quantitative measurement of changes in EEG frequency spectra produced in the cat by sedative-hypnotics and neuroleptics.

The sedative-hypnotic secobarbital and the sedative-anti-anxiety agent, chlordiazepoxide and two neuroleptics, chlorpromazine and halopridol, were treated for effects on the EEG of the cat using broad-band frequency analysis of 6 brain sites. Dose-related, 'drug-=specific' effects were abstracted from the data by the use of multivariate statistical techniques. These demonstrated that the two neuroleptic agents produced very similar alterations in the EEG frequency spectrum which were distinctly different from those resulting from the administration of the sedative-hypnotic and the sedative-anti-anxiety agent. The time-course of the central activity of the 4 compounds was also depicted.