Effects of paradoxical sleep deprivation and stress on the waking EEG of the rat.

Effects of 72 h of paradoxical sleep deprivation (PSD) and stress on the waking EEG of rats were studied using the water tank technique. EEG was recorded at left and right parietal cortex and the spectrum was analyzed before PSD, after 24, 48, and 72 h of PSD, and 24 h after recovery. Absolute and relative power and interparietal correlation were obtained. The same analyses were performed on a larger platform group and on a cold water-stressed group. The following significant changes were observed on the waking EEG: PSD produced a decrease in interparietal correlation, an increase in absolute and relative power between 7.3 and 9.3 Hz, and a decrease in the delta band relative power. The PSD effect on relative power was less specific on absolute power; relative power between 7.3 and 9.3 Hz was also increased in the large platform control group. Interparietal correlation was also decreased in both control groups but in the water-stressed animals it followed a different time course. The present findings suggest that PSD may affect brain function by increasing the level of hippocampal arousal, whereas the combination of stress and PSD affects interhemispheric coupling.