SLEEP-WAKE VARIABLES AND EEG POWER SPECTRA IN MONGOLIAN GERBILS AND WISTAR RATS

Using electroencephalographic methods (EEG), we have analyzed the basa l sleep structure and the EEG power spectra of gerbils and rats during periods of wakefulness (W), synchronized sleep (SS) and paradoxical s leep (PS). During the 6hr light period examined, duration of sleep was similar for rats and gerbils, but gerbils showed fewer PS episodes an d a longer amount of SS episodes followed by wakefulness. In addition, SS episodes preceding PS were of longer duration in gerbils than in r ats. EEG power spectral analysis indicated a higher relative output in the 1-4 Hz range in gerbils in comparison with rats. On the whole, th e data indicate the existence of significant differences in the basal sleep structure and EEG power spectra of gerbils and rats. This backgr ound information might be useful in the comparison of the effects of a given experimental treatment, such as cerebral ischemia, on the EEG a ctivity of these two animal species.