The Effects of Sensory Stimulation on REM Sleep Duration

Abstract

Previous experiments have demonstrated that auditory (AS) and/or somatosensory (SS) stimulation can increase the duration of REM sleep periods in rats, cats and humans. The objectives of this study were to determine whether repeated AS stimulation causes habituation to the stimulus and whether any additive effects could be obtained with the simultaneous application of AS and SS. Three experimental procedures were used in this study. In experiment 1, animals were recorded for 4 consecutive days with AS, followed by a post-stimulus session. In experiment 2, they were recorded for 24 hours with AS applied at each REM period, followed by a subsequent 24-hours-post-stimulus recording. In experiment 3, animals underwent AS, SS stimulation, or simultaneous application of both in a random fashion at each REM period. The results of all experiments confirm previous findings showing that auditory or somatosensory stimuli significantly increase REM sleep period duration. In addition, AS--applied with different presentations during REM and throughout the sleep-wake cycle--are capable of increasing REM duration regardless of the manner in which they were presented. However, the effects of the stimuli were not additive. It is worth noting that although REM duration increased, REM period frequency decreased, resulting in no net change of total REM sleep through time. Furthermore, no changes were observed in other sleep-wake variables. These experiments clearly demonstrate that repeated auditory stimulation does not cause habituation, and there are no evident side effects on the sleep-wake cycle. These results confirm that the mechanisms involved in REM generation and maintenance can be modulated by sensory modalities.

Functional microstates within human REM sleep: first evidence from fMRI of a thalamocortical network specific for phasic REM periods

“…Previous studies in animal models have reported controversial findings on transient increases (Drucker‐Colin et al ., 1983) or decreases (Mouze‐Amady et al ., 1986; Suntsova et al ., 2000) in phasic activity upon stimulation during REM sleep. Our findings support a phasic to tonic transition in response to acoustic stimuli, which can be explained by switching to a higher level of arousal with raised sensitivity to environmental changes, followed by subsequent re‐established phasic REM activity (Vazquez et al ., 1998; Suntsova et al ., 2000; Voss, 2004). This mechanism may also explain the high dropout rate of usable fMRI trials in the present study.…”

Muscarinic and GABAA receptors modulate acetylcholine release in feline basal forebrain

“…For microdialysis studies aiming to characterize changes in transmitter release as a function of sleep, cat is a logical choice because of the long duration NREM sleep and REM sleep epochs compared to rat or mouse. REM sleep epochs in cat last, on average, five to eight min (Ursin, 1968; Baghdoyan et al ., 1984; Lydic et al ., 1987; Vazquez et al ., 1998), thus permitting collection of dialysis samples during periods comprised entirely of REM sleep. Recent studies using cat have demonstrated that ACh release in the substantia innominata region of the basal forebrain is significantly greater during REM sleep than during wakefulness and NREM sleep (Vazquez & Baghdoyan, 2001).…”

Enhancement of REM sleep during extraocular light exposure in humans

“…In light of results from such studies, any hypotheses concerning effects of longerduration light administration on REM sleep must be regarded with caution. However, a study using auditory stimulation for varying durations and across multiple sleep periods in rats (45) indicated that there was no habituation effect to this stimulus, suggesting that further increases in REM sleep may be possible with more prolonged (or altered schedules) of photic stimulation.…”

“…Some reports have indicated that intense cognitive activity or visual stimulation before sleep onset increases REM sleep (6,43). In addition, a handful of studies in mammals (2,8,28,29,45), including one report in humans (33), indicates that various sensory stimuli administered during sleep result in acute REM-sleep enhancement.…”