The relationship between fasting-induced torpor, sleep and wakefulness in laboratory mice

Y Huang,S Flaherty,S Peirson,V Vyazovskiy

doi:10.1016/j.sleep.2019.11.446

Abstract

The relationship between fasting-induced torpor, sleep and wakefulness in laboratory mice

Highlights

States of vigilance in mammals are traditionally defined based on behavioral criteria and brain activity [1,2,3]
We performed a detailed investigation of EEG/EMG defined states of vigilance during hypothermia and torpor induced by restricted feeding in mice
Spectral EEG analysis revealed that cortical slowwave activity (SWA), which, in ET conditions, is a marker of sleep need that increases as a function of prior waking duration and decreases as a function of sleep, was typically high at the beginning of euthermia and declined thereafter. These findings suggested that the preceding torpor bout does not restore sleep need, which seems paradoxical as torpor is comprised predominantly of a state most similar to non-rapid eye movement (NREM) sleep

Summary

Introduction

States of vigilance in mammals are traditionally defined based on behavioral criteria and brain activity [1,2,3]. Sleep corresponds to a state of relative immobility and reduced sensory responsiveness, while wakefulness is characterized by movement and active engagement with the environment. These characteristics of an awake state are thought to be essential for its main functions, including feeding, mating, or defense against predation. Sleep is timed both by an endogenous circadian clock and by a homeostatic drive for sleep which builds during wake These two processes allow the alignment of numerous aspects of behavior and physiology with the occurrence of ecological factors such as light, food availability, ambient temperature, and risk of predation [8,9,10]

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Conclusion