ABSTRACT
The comparison of rapid eye movement (REM) and NonREM (NREM) mentation reports has remained one of the principal laboratory methods for studying dreaming processes. As the influence of cognitive science on sleep research has grown, experimental methods for comparing REM and NREM mentation have also evolved. Numerous studies have demonstrated the existence of cognitive activity during stages of sleep other than REM. Some of the strongest evidence for NREM cognition is that specific NREM contents are at times closely associated with pre-awakening stimuli. Phantom REM sleep may involve atypical NREM sleep episodes for which only one electrophysiological criterion earmarking it as REM sleep is lacking. REM sleep with high tonic chin muscle activity is a type of phantom REM sleep that in its most extreme form is known as REM sleep behavior disorder.
