Differential responding to the beta movement after waking from REM and nonREM sleep.

Ten young adults were wakened from REM sleep and from nonREM sleep on two nonconsecutive nights and were tested to determine their upper and lower beta-movement thresholds. The ranges of the illusion were found to be significantly wider after waking from REM sleep than after waking from nonREM sleep or before sleep. The differential responding to the beta movement supports the experimental hypothesis that apparent motion may provide sensitive detectors of the operation during wakefulness of the Basic Rest-Activity Cycle, of which REM and nonREM sleep are opposite phases that carry over into wakefulness.