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. Author manuscript; available in PMC: 2015 Nov 18.
Published in final edited form as: J Biol Rhythms. 2012 Feb;27(1):48–58. doi: 10.1177/0748730411431550

Figure 1.

Figure 1

Validation of immobility-defined sleep versus EEG/EMG-defined sleep. A) Experimental setup for the non-invasive assessment of sleep using digital video analysis. Mice were housed in light-tight chambers with light provided by a halogen light source through fibre optic cables. Miniature NIR cameras were mounted above each individual cage and were connected to a digital hard drive recorder and monitor. Video data was extracted from the hard drive recorder and analysed offline using commercially available video-tracking software (ANY-maze, Stoelting). B) Comparison of sleep assessed by digital video analysis (“Immob”) compared with EEG/EMG defined sleep (“EEG”) across a 24 hour baseline period under a 12:12 LD cycle for an individual mouse. C) Average immobility-defined sleep determined using digital video analysis and EEG/EMG in 6 mice. D) Bland-Altman plot displaying the mean difference (minutes) between the two methods used to assess sleep using the individual 30 minute values from B. The estimated bias across the 24 hour period was +0.24 minutes with a standard deviation of 2.93 minutes. The Bland-Altman 95% limits of agreement were −5.50 to +5.98 minutes. Data points were analysed in 30 minute periods to more accurately represent the polyphasic nature of sleep in mice. A similar high correlation was observed when analysed in 1h periods. In all cases sleep per 30min interval is shown and sensitivity was set at 95%.