Circadian rhythm in the EEG of man.

The circadian rhythm in the EEG of the waking state was investigated in six healthy volunteers who were deprived of sleep for 48 (3 probands) and 30 (3 probands) hours. Every hour an EEG was recorded, the body temperature was measured, and the probands rated their fatigue themselves. The EEG parameterized by the partial autocorrelation function shows a circadian change in all probands. The causal link between EEG and body temperature indicates that the circadian rhythm in the EEG is at least partly autonomous of external time cues and the sleep-wake cycle.