Is the nonREM–REM sleep cycle reset by forced awakenings from REM sleep?

Abstract

In selective REM sleep deprivation (SRSD), the occurrence of stage REM is repeatedly interrupted by short awakenings. Typically, the interventions aggregate in clusters resembling the REM episodes in undisturbed sleep. This salient phenomenon can easily be explained if the nonREM -REM sleep process is continued during the periods of forced wakefulness. However, earlier studies have alternatively suggested that awakenings from sleep might rather discontinue and reset the ultradian process. Theoretically, the two explanations predict a different distribution of REM episode duration.We evaluated 117 SRSD treatment nights recorded from 14 depressive inpatients receiving low dosages of Trimipramine. The alarms were triggered by an automatic mechanism for the detection of REM sleep and had to be canceled by the subjects themselves. The REM episodes were determined as in undisturbed sleep-they had to include the remaining REM activity and were separated by 30 min without REM epochs. The frequency histogram of REM episodes declined exponentially with episode duration for each of the first four sleep cycles. The duration of nonREM intervals revealed bimodal distributions. These results were found consistent with the model assuming a reset of the ultradian cycle upon awakening. Whether REM or nonREM activity is resumed on return to sleep can be modeled by a random decision whereby the probability for REM sleep might depend on the momentary REM pressure. D

Distinct effects of orexin receptor antagonist and GABA A agonist on sleep and physical/cognitive functions after forced awakening

“…In the placebo and brotizolam trials, the peak increase in the percentage of subjects in REM sleep was also observed at ∼190 min after the first bedtime, without the initial R stage shortly after going back to bed. We speculated that the NREM-REM cycle might be discontinued and reset by sleep interruption as previously observed (44,45) in the placebo and brotizolam trials, whereas suvorexant might have partially suppressed this resetting of the NREM-REM cycle.…”

A four-state Markov model of sleep-wakefulness dynamics along light/dark cycle in mice

“…have proposed that the need for rem increases exclusively during nrem , thus suggesting a somehow subservient function of rem [ 47 ]. In [ 48 ], the role of intrasleep awakenings in the resetting of nrem / rem ultradian process is proposed for supporting this view. Recently, transitions from N2 to N3 sleep have been proposed as a regulator of rem sleep onset [ 49 ].…”

Slow wave sleep and REM sleep awakenings do not affect sleep dependent memory consolidation

“…We chose a 2-min arousal, since after shorter awakenings subjects normally return immediately to the deprived sleep stage, and longer arousals have a too strong an effect on the total sleep time. 30,32 sleep data analysis For sleep data analysis, independent professional scorers scored the sleep stages using standard criteria. 31 In addition, EEG from the experimental nights underwent spectral analysis through a fast Fourier transformation, using in-house software.…”