An Ultradian Biologic Rhythm Associated With Perceptual Deprivation and REM Sleep

To demonstrate that the 10 to 20 cycle/day oscillations expressed during sleep by the cyclic occurrence of rapid-eye-movement periods may be present during wakefulness, 6 normal subjects were isolated for 36 hours. The electroencephalogram and several physiologic and behavioral indices were continuously recorded. After 8 hours of sleep, subjects attempted to remain awake and perform consistent behavioral tasks for 24 hours, but no subject could remain awake this entire interval. Data were analyzed with spectral analyses. Both during sleep and when the subjects were almost continuously awake, the 10 to 20 cycle/day frequency range was the predominant source of variance, indicating that a discrete 10 to 20 cycle/day oscillatory mechanism may modulate physiologic systems and behavior throughout the 24 hours.