REMS (rapid eye movement sleep)

Rapid Eye Movement (REM) is a stage of sleep following the earlier NREM (slow wave sleep) stages, so-called for the appearance of spontaneous rapid movement of the eyelids and eyes of a subject. This stage has the closest similarities with brain activity measured during waking states and is associated with stages of active dreaming, including lucid dreaming. Eugene Aserinsky (1921-1998), an American physiologist and hypnologist, is credited as being the first to investigate the phenomena scientifically while working at the University of Chicago in the early 1950s.

Reading

Aserinksy, et. al.

• Aserinsky, Eugene; Kleitman, Nathaniel (4 Sep. 1953), "Regularly Occurring Periods of Eye Motility, and Concomitant Phenomena, During Sleep", Science 118 (3062): 273-274 
• Aserinsky, Eugene; Kleitman, Nathaniel (1 Jul. 1955), "Two Types of Ocular Motility Occurring in Sleep", Journal of Applied Physiology 8 (1) 
• Aserinsky, Eugene (1969), "The Maximal Capacity for Sleep: Rapid Eye Movement Density as an Index of Sleep Satiety", Biological Psychiatry 1 (2): 147-159  — "The result of extending sleep beyond the usual quota was to increase the number of eye movements."
• Aserinsky, Eugene (Nov. 1973), "Relationship of Rapid Eye Movement Density to the Prior Accumulation of Sleep and Wakefulness", Psychophysiology 10 (6): 545-558  — "Ocular activity during the REM stage of sleep was studied for the purpose of determining what effect previous sleep and waking would have on the intensity of that activity[...] It was concluded that REM density reflects the output of a sleep-waking negative feedback circuit."
• Aserinsky, Eugene; Joan, A. Lynch; Mack, Michael E.; Tzankoff, Stephen P.; Hurn, Estil (Jan. 1985), "Comparison of Eye Motion in Wakefulness and REM Sleep", Psychophysiology 22 (1): 1-10  — "Rapid eye movements (REMs) in sleep have been postulated to represent ocular activity directly related to the visual imagery of dreaming. In accord with this notion, there have been reports that the physiological characteristics of REMs are identical to those of waking saccades which occur in the absence of visual targets. Contradictory evidence is herein presented establishing that REMs are significantly slower than waking saccades of comparable amplitude, and that this slowdown is greater than can be attributed to either eye closure or to eye movements in total darkness. Furthermore, it is shown that in REM sleep, both small (5.5°) and large (11°) saccade-like movements generate essentially the same maximal force and have the same velocity for the major portion of their trajectories. In sleep, therefore, there is probably a central inhibition of the saccade-like REMs, especially of the large amplitude movements, thus leading to an uncoupling of the usual amplitude-velocity relationship observed in the waking state."