Eye movements during sleep in weightlessness.
The number of eye movements during sleep increased during the first sleep period in zero gravity but returned to normal by the second night. These rapid-eye-movement functions in flight may be the first variations of an oscillatory system. The ratio of the higher and lower eye movement frequencies oscillates within normal-gravity limits.
D005133:Eye Movements; D006801:Humans; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D013026:Space Flight; D014893:Weightlessness