Cycle of Penile Erection Synchronous With Dreaming (REM) Sleep

Introduction The discovery of the dream-sleep cycle by Aserinsky and Kleitman1and Dement and Kleitman2is now well known. Briefly, it has been found that there are regularly recurring periods of sleep which are physiologically unique, showing a characteristic EEG pattern ( Stage 1) together with bursts of bilaterally synchronous, conjugate, rapid vertical and horizontal eye movements (REMs),*and that this physiological pattern is highly correlated with the sleeper's recall of detailed dream experiences. There are generally four or five such periods in an average night's sleep, dreaming taking up 20%-25% of the total sleep time. Further, the cyclic pattern of dreaming has been found to be relatively fixed and stable and universally present in the thousands of subjects that have by now been investigated in numerous laboratories. Fig 1 is a schematic representation of the dream-sleep cycle of a young adult, showing five REM dream-periods in an