Spectral analysis of mouse EEG after the administration of N,N-dimethyltryptamine

Mice were implanted with permanent cortical electrodes. The EEG was recorded during the sleep-wake cycle and after the administration of N,N-dimethyltryptamine (DMT). Based upon spectral analysis the EEG was classified into three categories: awake, slow-wave sleep (SWS), and rapid eye movement sleep (REM). The dominant frequencies were located below 2 Hz in the case of SWS and between 6 and 9 Hz for REM. When DMT was administered intraperitoneally at 20 or 40 mg/kg, a dose-dependent hypersynchrony at 2.5-4.5 Hz was always observed lasting for up to 60 min. Hypersynchronous activity in the same range was occasionally observed during awake. In this range DMT induced a different but unique frequency for each animal. This individual frequency was closely reproduced by repeated administrations of DMT to the same animal.