Sleep in the nocturnal primate, Aotus trivirgatus.

Measurement of the cycles of wakefulness and stages of sleep in owl monkeys during 24-hr periods divided into half dark and half light segments. Recordings of electrophysiological activity were used. Reversal of the sequence of light and dark served to test the influence of environmental lighting on the sleep-wakefulness cycles. The sleep patterns of owl monkeys expressed in percentage of rapid eye movement (REM) and nonrapid eye movement (NREM) were compared with those of a closely related New World monkey species, Saimiri Sciureus.