Rapid eye movement sleep in the brains of sleeping cats. In 1944, Ohlmeyer reported 90-minute ultradian sleep cycles involving male erections lasting for 25 minutes. At University of Chicago in 1952, Eugene Aserinsky, Nathaniel Kleitman, and William C. Dement, discovered phases of rapid eye movement during sleep, and connected these to dreaming. Their article was published September 10, 1953. Aserinsky, then Kleitman, first observed the eye movements and accompanying neuroelectrical activity in their own children. William Dement advanced the study of REM deprivation, with experiments in which subjects were awoken every time their EEG indicated the beginning of REM sleep. He published "The Effect
Recurrent thalamo-cortical resonance during REM. Measures of bulk electrical signalling in the brain by MEG show no impact of auditory stimuli on the gamma wave patterns; measurements on conscious subjects show a distinct modulation due to the auditory input. In this way, the thalamocortical system acts to gate the brain from external stimuli during REM. Non-rapid eye movement (NREM) sleep differs from REM in that gamma activity is no longer prominent, stepping aside for lower frequency oscillations. While electrical activity at gamma frequencies can occasionally be detected in NREM, it is infrequent and comes in bursts. The exact purpose of its appearance in