Measuring sociability of mice using a novel three-chamber apparatus and algorithm of the LABORAS™ system.

Background: The social approach and social novelty tests utilizing the three-chamber apparatus are widely accepted to measure social behavior of rodents. The LABORAS™ system offers a possibility to assess sociability of mice in a reliable and objective manner.

New Method: We assessed the capability of the LABORAS™ sociability cage and algorithm (2.6.6) to detect social behaviors in mice. Furthermore, we investigated whether the system is able to detect various levels of sociability due to genetic background or after pharmacological treatments.

Results: By comparing manual scoring with various detection zone settings of the automated registration, the most fitting algorithm with a detection zone radius of 90 mm was identified. When different strains were investigated, C57Bl/6 J and NMRI mice proved to be social, while CD1 mice were found asocial. The system was able to detect the sociability increasing effect of R-baclofen (0.5 mg/kg i.p.) and oxytocin (12 ng i.c.v.) in asocial CD1 mice. The negative control PCP impaired social behavior of C57Bl/6 J mice (1 mg/kg i.p.) and increased social avoidance in CD1 mice (0.3 mg/kg i.p.).

Comparison With Existing Method(s): This setup, in contrast to video frame analysis softwares, determines signal changes caused by movements of rodents allowing accurate detection and analysis of trajectories. Parallel automated measurements also allow replacing time and labor intensive, highly subjective human observational work.

Conclusions: The set-up provides a fast and reliable method to examine social behavior of mice in the three-chamber apparatus. The system is capable of detecting pro or antisocial activity of pharmacological agents.