Original Research ARTICLE
Sleep-wake cycle in young and older mice
- 1Department of Psychiatry and Neuroscience, Faculty of Medicine, Laval University, Canada
- 2Centre de recherche CERVO, Centre Intégré Universitaire de Santé et de Services Sociaux de la Capitale-Nationale (CIUSSSCN), Canada
- 3Centre d’études Avancées en Médecine du Sommeil, Hôpital du Sacré-Cœur de Montréal, Canada
- 4Independent researcher, Canada
- 5Department of Psychology, University of Montréal, Canada
- 6Department of Psychiatry and Neuroscience, Laval University, Canada
Sleep plays a key role in multiple cognitive functions and sleep pattern changes with aging. Human studies revealed that aging decreases sleep efficiency and reduces the total sleep time, the time spent in slow-wave sleep (SWS), and the delta power (1-4 Hz) during sleep; however, some studies of sleep and aging in mice reported opposing results. The aim of our work is to estimate how features of sleep-wake state in mice during aging could correspond to age-dependent changes observed in human. In this study we investigated the sleep/wake cycle in young (3 months old) and older (12 months old) C57BL/6 mice using local-field potentials (LFP). We found that older adult mice sleep more than young ones but only during the dark phase of sleep-wake cycle. Sleep fragmentation and sleep during the active phase (dark phase of cycle), homologous to naps, were higher in older mice. Older mice show a higher delta power in frontal cortex, which was accompanied with similar trend for age differences in slow wave density. We also investigated regional specificity of sleep-wake electrographic activities and found that globally posterior regions of the cortex show more REM sleep whereas somatosensory cortex displays more often SWS patterns. Our results indicate that the effects of aging on the sleep-wake activities in mice occur mainly during the dark phase and the electrode location strongly influence the state detection. Despite some differences in sleep-wake cycle during aging between human and mice, some features of mice sleep share similarity with human sleep during aging.
Keywords: sleep-wake cycle, LFP, Delta power, Slow-wave sleep (SWS), REM (Rapid Eye Movement) sleep, wake, sleep fragmentation
Received: 09 May 2019;
Accepted: 09 Sep 2019.
Copyright: © 2019 Soltani, Chauvette, Bukhtiyarova, LINA, Dubé, Seigneur, Carrier and Timofeev. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Igor Timofeev, Laval University, Department of Psychiatry and Neuroscience, Quebec, G1K 7P4, Canada, firstname.lastname@example.org