Quantitative investigation reveals distinct phases in Drosophila sleep

Xiuwen Sui,Yi Rao,Xiaochan Xu,Wei Yang,Chao Tang,Binghui Tian,Weilai Chi

doi:10.1038/s42003-021-01883-y

Abstract

The fruit fly, Drosophila melanogaster, has been used as a model organism for the molecular and genetic dissection of sleeping behaviors. However, most previous studies were based on qualitative or semi-quantitative characterizations. Here we quantified sleep in flies. We set up an assay to continuously track the activity of flies using infrared camera, which monitored the movement of tens of flies simultaneously with high spatial and temporal resolution. We obtained accurate statistics regarding the rest and sleep patterns of single flies. Analysis of our data has revealed a general pattern of rest and sleep: the rest statistics obeyed a power law distribution and the sleep statistics obeyed an exponential distribution. Thus, a resting fly would start to move again with a probability that decreased with the time it has rested, whereas a sleeping fly would wake up with a probability independent of how long it had slept. Resting transits to sleeping at time scales of minutes. Our method allows quantitative investigations of resting and sleeping behaviors and our results provide insights for mechanisms of falling into and waking up from sleep.

Highlights

The fruit fly, Drosophila melanogaster, has been used as a model organism for the molecular and genetic dissection of sleeping behaviors
As a simple yet powerful model system, the study of fruit fly sleep behavior has led to the discoveries of important genes and mechanisms, which are conserved in mammals[13,14,15]
The sleep pattern we found was prevalent for all flies, but the five parameters β, λ, K, N, and total time (Total) characterizing the pattern could be different for each individual fly and may vary between day and night, and between male and female (Fig. 3)

Summary

Introduction

The fruit fly, Drosophila melanogaster, has been used as a model organism for the molecular and genetic dissection of sleeping behaviors. A unique threshold for all flies is questionable, especially for studies including mutants that are supposed to change their sleep behavior either in the latency phase or sleep phase This standard will confound mutants with shorter latency and mutants with shorter sleep time[18]. For the long-term rest behavior associated with the sleep phase, the power law is not an accurate characterization of the temporal structure[20]. Including the power law distribution in the latent phase, we concluded a generic sleep pattern of the fruit flies. This pattern described an intrinsic law of the whole sleep process and gave parameters to characterize single fly’s sleep properties quantitatively. Our program could detect the flies even when they walked along the edges of the chambers

Methods

Results

Conclusion