Increased accuracy of binocular depth perception following REM sleep periods.

Abstract

ABSTRACTIt has been proposed that REM sleep maintains facilitation of coordinated eye movements necessary for accurate binocular depth perception (Berger, 1969). This experiment confirmed the prediction that binocular depth perception would be more accurate at the ends of REM periods than at their onsets. Eight male subjects were studied during 4 non‐consecutive nights of sleep. Accuracy of binocular and monocular depth perception were measured with different apparatus in the evening prior to sleep onset, after awakenings made alternately at the onsets or ends of REM periods, and 15 min after awakening in the morning. Accuracy of binocular depth perception was significantly better at the ends of REM periods than at their onsets (p < .001), whereas accuracy of monocular depth perception did not significantly differ. That the monocular task was sensitive to variables of sleep was indicated by impairment at the first REM onset with little variation throughout the night, so that it was significantly worse 15 min after morning awakening than the previous evening (p < .05). In contrast, accuracy of binocular depth perception was significantly better in the morning than the previous evening and at REM onsets (p < .05).