Ultrasonic vocalisations during rapid eye movement sleep in the rat

Fabio Squarcio; Timna Hitrec; Marco Luppi; Davide Martelli; Alessandra Occhinegro; Emiliana Piscitiello; Ludovico Taddei; Domenico Tupone; Roberto Amici; Matteo Cerri

doi:10.1111/jsr.13993

Ultrasonic vocalisations during rapid eye movement sleep in the rat

J Sleep Res. 2023 Jul 10:e13993. doi: 10.1111/jsr.13993. Online ahead of print.

Affiliations

¹ Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
² School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, UK.

PMID: 37430421
DOI: 10.1111/jsr.13993

Abstract

Rats are known to use a 22-kHz ultrasonic vocalisation as a distress call to warn of danger to other members of their group. We monitored 22-kHz ultrasonic vocalisation emissions in rats (lean and obese) as part of a sleep deprivation study to detect the eventual presence of stress during the procedure. Unexpectedly, we detected ultrasonic vocalisation emission during rapid eye movement (REM) sleep, but not during non-REM (NREM) sleep, in all the rats. The event occurs during the expiratory phase and can take place singularly or as a train. No difference was detected in the number or duration of these events in lean versus obese rats, during the light versus the dark period, and after sleep deprivation. As far as we know, this is the first report showing that rats can vocalise during REM sleep.

Keywords: diaphragm EMG; high-fat diet; sleep deprivation.