3-D motion capture for long-term tracking of spontaneous locomotor behaviors and circadian sleep/wake rhythms in mouse

[Display omitted] •Simultaneous tracking of locomotor movement in tens of freely behaving animals in their home cages.•Does not require separate monitoring devices for the individual animal.•A cost effective system for making continuous and fully automated long-term recordings (up to 3 months).•Capability of recording at all ambient light levels, including during darkness, with high spatial and temporal resolution.•Actigraphy-based movement detection allows for the analysis of sleep patterns and circadian rhythms. Locomotor activity provides an index of an animal's behavioral state. Here, we report a reliable and cost-effective method that allows long-term (days to months) simultaneous tracking of locomotion in mouse cohorts (here consisting of 24 animals). The technique is based on a motion capture system used mainly for human movement study. A reflective marker was placed on the head of each mouse using a surgical procedure and labeled animals were returned to their individual home cages. Camera-recorded data of marker displacement resulting from locomotor movements were then analyzed with custom built software. To avoid any data loss, data files were saved every hour and automatically concatenated. Long-term recordings (up to 3 months) with high spatial (