EEG spectral power in phasic and tonic REM sleep: different patterns in young adults and children

Abstract

SUMMARYRapid eye movement sleep is composed of phasic and tonic periods, two distinguishable microstates in terms of arousal thresholds and sensory processing. Background electroencephalogram oscillations are also different between periods with (phasic state) and periods without (tonic state) eye movements. In Study 1, previous findings analysing electroencephalogram spectral power in phasic and tonic rapid eye movement sleep were replicated, and analyses extended to the high gamma range (52-90 Hz). In Study 2, phasic and tonic spectral power differences within a group of 4-8-year-old children were examined. Based on the polysomnographic data of 20 young adults, the phasic state yielded increased delta and theta power in anterior sites, as well as generally decreased high alpha and beta power in comparison to the tonic state. Moreover, phasic periods exhibited greater spectral power in the lower and the higher gamma band. Interestingly, children (n = 18) exhibited a different pattern, showing increased activity in the low alpha range during phasic periods. Moreover, during phasic in contrast to tonic rapid eye movement sleep, increased low and high gamma and enhanced low gamma band power emerged in anterior and posterior regions, respectively. The current findings show that spectral activity within the high gamma range substantially contributes to the differences between phasic and tonic rapid eye movement sleep, especially in adults. Moreover, the current data underscore the heterogeneity of rapid eye movement sleep, and point to marked differences between young adults and children regarding phasic/tonic electroencephalogram spectral power. These results suggest that the differentiation between phasic and tonic rapid eye movement periods undergoes maturation.

The Spectral Fingerprint of Sleep Problems in Post-Traumatic Stress Disorder

“…Previous studies have reported increased REM sleep delta (0.5-4Hz) in nightmare disorder (69), and in association with sleep onset hypnagogic imagery (70). Furthermore, delta power is higher in phasic compared to tonic REM sleep (71); the former being the part of REM sleep marked by REMs and hosting most active dreaming (72). The combined findings suggest that increased REM sleep SO power in PTSD patients is related to the frequent nightmares and/or coconcurrently increased REMs.…”

Ketamine effects on default mode network activity and vigilance: A randomized, placebo‐controlled crossover simultaneous fMRI/EEG study

“…Light sleep or sleep stage 1 (according to Rechtschaffen & Kales, 1968) is a transitory and dynamic stage between wake and sleep, it is an unstable (arousable) sleep stage with relatively frequent so-called cyclic alternating patterns (CAPs) compared to deep sleep (Terzano et al, 2001). In EEG, CAPs are characterized by transient slow wave oscillations (i.e., decreased vigilance) but also intermittent low amplitude high frequency oscillations up the gamma frequency range, that is, desynchronized EEG vigilance (Parrino, Grassi, & Milioli, 2014;Simor, Gombos, Szakadát, Sándor, & Bódizs, 2016). Interestingly, Ferri, Rundo, Bruni, Terzano, and Stam (2007) could show that the slow wave CAPs possess small world properties with high cluster coefficient and small path length.…”

The paradox of Rapid Eye Movement sleep in the light of oscillatory activity and functional synchronization during phasic and tonic microstates

“…Previous studies examining spontaneous oscillatory activity during phasic and tonic REM periods consistently found elevated levels in alpha (8 J 13 Hz) and beta (14 J 30 Hz) EEG power (Waterman et al, 1993; Jouny et al, 2000; De Carli et al, 2016; Simor et al, 2016) and synchronization (Simor et al, 2018) during tonic periods. These data suggest that tonic REM is closer to quiet wakefulness with regard to cortical oscillations.…”

“…Phasic microstates with ocular movements, muscle twitches and vegetative irregularities are interspersed among longer and apparently more quiescent tonic periods. Several studies indicate that phasic and tonic REM sleep microstates are markedly different neural states as regarding awakening thresholds (Ermis et al, 2010), spontaneous oscillatory activity (Simor et al, 2016, 2018), information processing (Sallinen et al, 1996; Andrillon et al, 2017), and even mental experiences (Molinari and Foulkes, 1969; Stuart and Conduit, 2009).…”

“…Accordingly, reactivity to external (auditory) stimulation seems to be partially preserved during tonic states in contrast to phasic periods that appear as a functionally isolated state (Wehrle et al, 2007), detached from the environment (Sallinen et al, 1996; Ermis et al, 2010). On the other hand, relatively higher (> 31 Hz) gamma band power distinguished phasic from tonic microstates (Jouny et al, 2000; Abe et al, 2008; Simor et al, 2016). Enhanced gamma activity during phasic microstates was assumed to reflect sensorimotor, emotional and cognitive processes leading to intense dreaming (Gross and Gotman, 1999; Abe et al, 2008; Corsi-Cabrera et al, 2016).…”