Investigation of sleep–wake rhythm in non-human primates without restraint during data collection

Abstract

To understand sleep mechanisms and develop treatments for sleep disorders, investigations using animal models are essential. The sleep architecture of rodents differs from that of diurnal mammals including humans and non-human primates. Sleep studies have been conducted in non-human primates; however, these sleep assessments were performed on animals placed in a restraint chair connected via the umbilical area to the recording apparatus. To avoid restraints, cables, and other stressful apparatuses and manipulations, telemetry systems have been developed. In the present study, sleep recordings in unrestrained cynomolgus monkeys (Macaca fascicularis) and common marmoset monkeys (Callithrix jacchus) were conducted to characterize normal sleep. For the analysis of sleep–wake rhythms in cynomolgus monkeys, telemetry electroencephalography (EEG), electromyography (EMG), and electrooculography (EOG) signals were used. For the analysis of sleep–wake rhythms in marmosets, telemetry EEG and EOG signals were used. Both monkey species showed monophasic sleep patterns during the dark phase. Although non-rapid eye movement (NREM) deep sleep showed higher levels at the beginning of the dark phase in cynomolgus monkeys, NREM deep sleep rarely occurred during the dark phase in marmosets. Our results indicate that the use of telemetry in non-human primate models is useful for sleep studies, and that the different NREM deep sleep activities between cynomolgus monkeys and common marmoset monkeys are useful to examine sleep functions.

Communication from the cerebellum to the neocortex during sleep spindles

“…The proportion of REM/arousal periods derived using this method ( Fig. 5 A) is comparable to previously reported results for monkeys ( Ishikawa, Sakai et al 2017 ). Note that this method does not allow us to distinguish between REM and arousal states, but allowed us to exclude both from subsequent analysis of non-REM sleep.…”

Sleep Disorders in Children With Autism Spectrum Disorder: Insights From Animal Models, Especially Non-human Primate Model

“…And also, PSG instruments are bulky and expensive and may be difficult to monitor changes in patients for long-term studies ( Stepnowsky et al, 2013 ; Qin et al, 2020 ). Recently, telemetry transmitters have been used for long-term measuring of EEG and electromyography signals in rodent and NHP animals, it could collect data from conscious, freely moving laboratory animals without skin-electrode contact impedance and reduce animals’ stress ( Ishikawa et al, 2017 ; Qiu et al, 2019 ). This strategy can be potentially applied for future clinical applications.…”

Simplified drug efficacy screening system for sleep-disorder drugs using non-human primates

“…Hence, mice and rats are different from humans, which are diurnal animals with a monophasic sleeping pattern-i.e., they sleep once per day [14]. Monkeys also sleep several times a day, but they are also diurnal animals [15] and exhibit the most similar sleeping pattern to humans compared to other experimental animals. When conducting a sleeping experiment where activities of drug-metabolizing enzymes differ among animal species [16], and particularly when an analysis regarding addiction is concerned, sufficient consideration of the test animal model is mandatory.…”

“…Polysomnographic data have been recorded from non-human primates using telemetry implants [17,18]. Although telemetry is a remote system that enables the electronic capture of biological signals in freely moving animals, which leads to reduced stress and changes in sleep characteristics [15], telemetry involves complex surgical implantation of electrodes that are relayed to a biosensor device (transmitter) positioned subcutaneously, intramuscularly, or intraperitoneally. Sleep architecture follows an alternating cycle of rapid eye movement (REM) and non-rapid eye movement (NREM) sleep throughout a typical night and is defined in the laboratory by recording the electrical field activity of large groups of neurons and muscle cells in humans and model animals [19,20].…”