Bouts of rest and physical activity in C57BL/6J mice

The objective was to exploit the raw data output from a scalable home cage (type IIL IVC) monitoring (HCM) system (DVC®), to characterize the pattern of undisrupted rest and physical activity (PA) of C57BL/6J mice. The system’s tracking algorithm shows that mice in isolation spend 67% of the time in bouts of long rest (≥40s) and 59% of the time was interpreted as sleep. Twenty percent is physical activity (PA), split equally between local movements and locomotion. Decomposition revealed that a day contains ~6500 discrete bouts of short and long rest, and local and locomotor movements. Mice travel ~330m per day, mainly during the dark hours, while travelling speed is similar through the light-dark cycle. Locomotor bouts are usually <0.2m and <1% are >1m. Tracking also revealed fits of abnormal behaviour. The starting positions of the bouts showed no preference for the rear over the front of the cage floor, while there was a strong bias for the peripheral (75%) over the central f..., ,