Inactive but awake behaviour as indicating a depression-like state in mice: Aetiological factors and association with adult hippocampal neurogenesis

In laboratory mice, ‘inactive but awake’ (IBA) home-cage behaviour involves animals being spontaneously motionless with eyes open, not interacting with their surroundings. Conventional (barren) housing typically triggers IBA more than comparatively enriched environments. Compellingly greater IBA is associated with some depression-like features in mice and we further explored this through three aims. First, we aimed to replicate previous results highlighting environmental and genetic (using two strains of mice: DBA/2J and C57BL/6J) aetiological contributors to IBA. Second, we explored whether the performance of IBA varied as the level of enrichment was either increased or reduced. Third, we opportunistically investigated whether elevated IBA predicted lower density of immature neurons in the dorsal (dDG) or ventral dentate gyrus (vDG) of the hippocampus. As expected, mice housed in conventional cages displayed more IBA than those in comparatively enriched cages and even more so in DBA/2J..., , # Inactive but awake behaviour as indicating a depression-like state in mice: Aetiological factors and association with adult hippocampal neurogenesis

Dataset DOI: [10.5061/dryad.8cz8w9h59](10.5061/dryad.8cz8w9h59)

## Description of the data and file structure

*Animals, housing and husbandry*

Thirty-one female C57BL/6J (C57, hereafter) and 31 female DBA/2J (DBA, hereafter) mice were pair-housed post-weaning in either highly enriched (N = 15 cages) or non-enriched (N = 16 cages) transparent *Techniplast* cages.

*Behavioural scan sampling of mice*

The behaviour relevant to the hypothesis under test was being *inactive but awake* (IBA hereafter), defined  as ‘mouse motionless, muzzle in sight and eyes open, for at least 15s’. All observations were conducted during the animals’ dark (active) phase under red ambient light, for three weeks, four days per week, over four 90-minute time blocks per day: 9:30-11:00, 11:30-13:00, 13:45-15:15, 15:45-17:15. Behaviour was recorded *via* live sc...,