title: Novel method for high-throughput phenotyping of sleep in mice.
abstract: Assessment of sleep in mice currently requires initial implantation of chronic electrodes for assessment of electroencephalogram (EEG) and electromyogram (EMG) followed by time to recover from surgery. Hence, it is not ideal for high-throughput screening. To address this deficiency, a method of assessment of sleep and wakefulness in mice has been developed based on assessment of activity/inactivity either by digital video analysis or by breaking infrared beams in the mouse cage. It is based on the algorithm that any episode of continuous inactivity of > or =40 s is predicted to be sleep. The method gives excellent agreement in C57BL/6J male mice with simultaneous assessment of sleep by EEG/EMG recording. The average agreement over 8,640 10-s epochs in 24 h is 92% (n = 7 mice) with agreement in individual mice being 88-94%. Average EEG/EMG determined sleep per 2-h interval across the day was 59.4 min. The estimated mean difference (bias) per 2-h interval between inactivity-defined sleep and EEG/EMG-defined sleep was only 1.0 min (95% confidence interval for mean bias -0.06 to +2.6 min). The standard deviation of differences (precision) was 7.5 min per 2-h interval with 95% limits of agreement ranging from -13.7 to +15.7 min. Although bias significantly varied by time of day (P = 0.0007), the magnitude of time-of-day differences was not large (average bias during lights on and lights off was +5.0 and -3.0 min per 2-h interval, respectively). This method has applications in chemical mutagenesis and for studies of molecular changes in brain with sleep/wakefulness.
authors.affiliation: Center for Sleep and Respiratory Neurobiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA. pack@mail.med.upenn.edu
authors.forename: Allan I
authors.initials: AI
authors.lastname: Pack
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Galante
authors.forename: Greg
authors.initials: G
authors.lastname: Maislin
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Cater
authors.forename: Dimitris
authors.initials: D
authors.lastname: Metaxas
authors.forename: Shan
authors.initials: S
authors.lastname: Lu
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Randy
authors.initials: R
authors.lastname: Von Smith
authors.forename: Timothy
authors.initials: T
authors.lastname: Kay
authors.forename: Jie
authors.initials: J
authors.lastname: Lian
authors.forename: Karen
authors.initials: K
authors.lastname: Svenson
authors.forename: Luanne L
authors.initials: LL
authors.lastname: Peters
mesh_terms: D000465:Algorithms; D000818:Animals; D004569:Electroencephalography / Q000379:methods*; D004576:Electromyography / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D015203:Reproducibility of Results; D012890:Sleep / Q000502:physiology*; D014741:Video Recording / Q000379:methods; D014851:Wakefulness / Q000502:physiology*