Aperiodic neural activity distinguishes between phasic and tonic REM sleep
J Sleep Res. 2024 Dec 26:e14439.
DOI: https://doi.org/10.1111/jsr.14439
Yevgenia Rosenblum1, Tamás Bogdány2,3, Lili Benedikta Nádasy2, Xinyuan Chen1, Ilona Kovács4, Ferenc Gombos4,5, Péter Ujma6, Róbert Bódizs6, Nico Adelhöfer1, Péter Simor 2,6, Martin Dresler1
1 Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behavior, Nijmegen, Netherlands
2 Institute of Psychology, ELTE Eötvös Loránd University, Budapest, Hungary
3 Doctoral School of Psychology, ELTE, Eötvös Loránd University, Budapest, Hungary
4 HUN-REN-ELTE-PPKE Adolescent Development Research Group, Faculty of Education and Psychology, Eötvös Loránd University, Budapest, Hungary
5 Pázmány Péter Catholic University, Department of General Psychology, Budapest, Hungary
6 Semmelweis University, Institute of Behavioural Sciences, Budapest, Hungary
SUMMARY
Traditionally categorized as a uniform sleep phase, rapid eye movement sleep exhibits substantial heterogeneity with its phasic and tonic constituents showing marked differences regarding many characteristics. Here, we investigate how tonic and phasic states differ with respect to aperiodic neural activity, a marker of arousal and sleep. Rapid eye movement sleep heterogeneity was assessed using either binary phasic-tonic (n = 97) or continuous (in 60/97 participants) approach. Slopes of the aperiodic power component were measured in the low (2–30 Hz, n = 97) and high (30–48 Hz, n = 60/97) frequency bands with the Irregularly Resampled Auto[1]Spectral Analysis applied on electroencephalography. Rapid eye movement ampli[1]tudes were quantified with the YASA applied on electrooculography (n = 60/97). The binary approach revealed that the phasic state is characterized by steeper low[1]band slopes with small effect sizes and some topographical heterogeneity over data[1]sets. High-band aperiodic slopes were flatter in the phasic versus tonic state with medium-to-large effect sizes over all areas in both datasets. The continuous approach confirmed these findings. The temporal analysis within rapid eye movement episodes revealed that aperiodic activity preceding or following EM events did not cross[1]correlate with eye movement amplitudes. This study demonstrates that aperiodic slopes can serve as a reliable marker able to differentiate between phasic and tonic constituents of rapid eye movement sleep and reflect phasic rapid eye movement event intensity. However, rapid eye movement events could not be predicted by preceding aperiodic activity and vice versa, at least not with scalp electroencephalography.
KEYWORDS
1/f, aperiodic activity, electroencephalogram, polysomnography, rapid eye movement, rapid eye movement sleep, scale-free, sleep