Noninvasive, High-throughput Determination of Sleep Duration in Rodents

Abstract

Traditionally, sleep is monitored by an electroencephalogram (EEG). EEG studies in rodents require surgical implantation of the electrodes followed by a long recovery period. To perform an EEG recording, the animal is connected to a receiver, creating an unnatural tether to the head-mount. EEG monitoring is time consuming, carries risk to the animal, and is not a completely natural setting for the measurement of sleep. Alternative methods to detect sleep, particularly in a high-throughput fashion, would greatly advance the field of sleep research. Here, we describe a validated method for detecting sleep via activity-based home-cage monitoring. Previous studies have shown that sleep assessed via this method has a high degree of agreement with sleep defined by traditional EEG-based measures. Whereas this method is validated for total sleep time, it is important to note that sleep bout duration should be assessed by an EEG which has better temporal resolution. The EEG can also differentiate rapid eye movement (REM) and non-REM sleep, giving more detail about the exact nature of sleep. Nevertheless, activity-based sleep determination can be used to analyze multiple days of undisturbed sleep and to assess sleep as a response to an acute event (like stress). Here, we show the power of this system to detect the response of mice to daily intraperitoneal injections.

Noninvasive three-state sleep-wake staging in mice using electric field sensors

“…Though mouse sleep can be measured using other noninvasive approaches, EF sensor recordings have the additional ability to simultaneously quantify other motor behaviors such as ventilation profiles in non-REM and REM sleep, grooming, locomotion, eating, and drinking using only a frequency-based features of a single voltage channel. 31 Other noninvasive movement-based methods to measure rodent sleep have been reported using video, [18][19][20]22,43 whole body plethysmography, 7,11 infrared beams, 19,44 pulse Doppler radar, 21 piezoelectric films, 10,24,[45][46][47] and actimetry. 48,49 Several of these approaches, namely video, infrared beams, and actimetry, cannot distinguish non-REM from REM sleep 18,19,22,[43][44][45][46][47][48][49] limiting their applications to when only sleep/wake discrimination is sufficient.…”

“…31 Other noninvasive movement-based methods to measure rodent sleep have been reported using video, [18][19][20]22,43 whole body plethysmography, 7,11 infrared beams, 19,44 pulse Doppler radar, 21 piezoelectric films, 10,24,[45][46][47] and actimetry. 48,49 Several of these approaches, namely video, infrared beams, and actimetry, cannot distinguish non-REM from REM sleep 18,19,22,[43][44][45][46][47][48][49] limiting their applications to when only sleep/wake discrimination is sufficient. Of the published studies capable of noninvasively measuring 3state sleep architecture, the reported overall accuracies to EEG/EMG range from 84% to 91%, 10,11,20,21,24 .…”

Sleep Duration in Mouse Models of Neurodevelopmental Disorders

“…At 60–77 days of age, we assessed sleep duration by means of the home-cage activity monitoring system (Comprehensive Laboratory Animal Monitoring System (CLAMS)) (Columbus Instruments, Columbus, OH, USA) as previously described [ 20 ]. Briefly, mice were singly housed in a standard mouse cage for the duration of the sleep assessment.…”

Chronic Sleep Restriction in Developing Male Mice Results in Long Lasting Behavior Impairments

“…Animals were separated into individual standard mouse cages and placed in the activity monitoring system (CLAMS) (Columbus Instruments, Columbus, OH, United States) for 72 h. To allow for habituation to the single housing and monitoring system, only the last 48 h-period was analyzed (Sare et al, 2018). Activity was recorded in 10 s epochs.…”