Sleep, zsab100; DOI: 10.1093/sleep/zsab100; Published: 19 April 2021
Péter Simor1,2,3, Tamás Bogdány1, Róbert Bódizs2,4, Pandelis Perakakis5,6
1 Institute of Psychology, ELTE, Eötvös Loránd University, Budapest, Hungary
2 Institute of Behavioural Sciences, Semmelweis University, Budapest, Hungary
3 UR2NF, Neuropsychology and Functional Neuroimaging Research Unit at CRCN – Center for Research in Cognition and Neurosciences and UNI – ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium
4 National Institute of Clinical Neurosciences, Budapest, Hungary
5 Department of Social, Organisational, and Differential Psychology, Complutense University of Madrid, Spain
6 Brain, Mind, & Behavior Research Center, University of Granada, Spain
ABSTRACT
Sleep is a fundamental physiological state that facilitates neural recovery during periods of attenuated sensory processing. On the other hand, mammalian sleep is also characterized by the interplay between periods of increased sleep depth and environmental alertness. Whereas the heterogeneity of microstates during non-rapid-eye-movement (NREM) sleep was extensively studied in the last decades, transient microstates during REM sleep received less attention. REM sleep features two distinct microstates: phasic and tonic. Previous studies indicate that sensory processing is largely diminished during phasic REM periods, whereas environmental alertness is partially reinstated when the brain switches into tonic REM sleep. Here, we investigated interoceptive processing as quantified by the heartbeat evoked potential (HEP) during REM microstates. We contrasted the HEPs of phasic and tonic REM periods using two separate databases that included the nighttime polysomnographic recordings of healthy young individuals (N = 20 and N = 19). We find a differential HEP modulation of a late HEP component (after 500 ms post-R-peak) between tonic and phasic REM. Moreover, the late tonic HEP component resembled the HEP found in resting wakefulness. Our results indicate that interoception with respect to cardiac signals is not uniform across REM microstates, and suggest that interoceptive processing is partially reinstated during tonic REM periods. The analyses of the HEP during REM sleep may shed new light on the organization and putative function of REM microstates.
Keywords:
Heartbeat evoked potential, sleep, REM, interoception, microstates