Context-specific comparison of sleep acquisition systems in Drosophila.

David S Garbe,Alex C Keene,Jill Gertowski,Wesley L Bollinger,Pavel Masek,Abigail Vigderman,Amita Sehgal

doi:10.1242/bio.013011

Abstract

ABSTRACTSleep is conserved across phyla and can be measured through electrophysiological or behavioral characteristics. The fruit fly, Drosophila melanogaster, provides an excellent model for investigating the genetic and neural mechanisms that regulate sleep. Multiple systems exist for measuring fly activity, including video analysis and single-beam (SB) or multi-beam (MB) infrared (IR)-based monitoring. In this study, we compare multiple sleep parameters of individual flies using a custom-built video-based acquisition system, and commercially available SB- or MB-IR acquisition systems. We report that all three monitoring systems appear sufficiently sensitive to detect changes in sleep duration associated with diet, age, and mating status. Our data also demonstrate that MB-IR detection appeared more sensitive than the SB-IR for detecting baseline nuances in sleep architecture, while architectural changes associated with varying life-history and environment were generally detected across all acquisition types. Finally, video recording of flies in an arena allowed us to measure the effect of ambient environment on sleep. These experiments demonstrate a robust effect of arena shape and size as well as light levels on sleep duration and architecture, and highlighting the versatility of tracking-based sleep acquisition. These findings provide insight into the context-specific basis for choosing between Drosophila sleep acquisition systems, describe a novel cost-effective system for video tracking, and characterize sleep analysis using the MB-IR sleep analysis. Further, we describe a modified dark-place preference sleep assay using video tracking, confirming that flies prefer to sleep in dark locations.

Highlights

Tracking systems and MB monitoring are capable of detecting movement throughout an arena and have the potential to be more sensitive than the traditional SB-IR Drosophila Activity Monitors (DAM) system in detecting sleep
The results from this study provide a detailed comparison of behavioral quiescence as measured across sleep acquisition systems
Our results indicate that under standard conditions measurements of sleep architecture obtained using MB (‘Movement’ parameter; Fig. 1D,E, Fig. 2) and our video tracking system are more sensitive than SB-IR

Summary

Introduction

2000; Zhdanova et al, 2001; Raizen et al, 2008) These models are proving to be extremely useful as their genetic amenability is leading to the identification of genes and molecules involved in sleep-wake regulation (Sehgal and Mignot, 2011; Allada and Siegel, 2008; Cirelli, 2009; Griffith, 2013). Traditional SB DAM acquisition is unable to determine location preference within a recording chamber and cannot recognize small movements during periods of quiescence. To address these concerns a new generation of DAM monitors have been developed that detect movement throughout the entire arena using 17 distinct IR beams. Differences in acquisition sensitivity and accuracy between these IRbased systems have not been investigated

Methods

Results

Conclusion