Sleep–Wake Cycle in Young and Older Mice

Abstract

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 (LFPs). 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 rapid eye movement (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.

Slow Wave Sleep Is a Promising Intervention Target for Alzheimer’s Disease

“…On the other hand, aging mice also exhibit similarities to aging humans. For example, aged mice exhibit increases in sleep fragmentation, increases in sleep duration during active phase of sleep-wake cycle (light for humans, dark for mice), and decreased REM sleep at the end of quiet phase of sleep-wake cycle (Soltani et al, 2019). Thus use of mouse models should be considered with caution when modeling human condition.…”

Melatonin ameliorates the sleep disorder induced by surgery under sevoflurane anaesthesia in aged mice

“…Sleep patterns change with ageing 27 . Animal studies have revealed that aged mice sleep more than young‐adult mice during the dark phase, and that sleep fragmentation and sleep during the active phase occurred more in aged mice 28 . To our knowledge, the baseline data reported in this study are the first to show the sleep pattern of 18‐month‐old female C57BL/6J mice.…”

Kamikihito Enhances Cognitive Functions and Reward-Related Behaviors of Aged C57BL/6J Mice in an Automated Behavioral Assay System

“…Of numerous neural networks relevant to the balance of arousal and sleep (Sakurai, 2007;Scammell et al, 2017), the wake-promoting orexinergic neurons are noteworthy as potential targets of KKT, as spinosin, a major ingredient of Ziziphi Semen (ZS), reduces the activation of orexinergic neurons in the lateral hypothalamic area (Zhang et al, 2019). Regarding the influence of aging, older mice exhibited a decrease in rapid eye movement (REM) sleep during the early part of the light phase compared to that in younger mice (Wimmer et al, 2013;Soltani et al, 2019). In this regard, reduced quality of REM sleep in a rat AD model, reflected by a decrease in theta power density during REM sleep, was ameliorated by the Kampo medicine sansoninto, which includes ZS as a major component (Moriyama et al, 2017).…”