Complex social behaviour during an extended period of time in a valproic acid animal model of autism spectrum disorder

Autism Spectrum Disorder (ASD) is a progressive neurodevelopmental disorder characterized mainly by deficits in social communication and stereotyped and restricted interests. Deficits in social interactions in ASD animal models are generally analysed using the three chamber’s test paradigm that is simple to implement and use but fails to detect subtle social deficits or complex social behavior on an extended period of time within a group of mice. Here, we set up a novel procedure entitled the Live Mouse Tracker (LMT) that detects a great number of complex social behaviours that we recorded continuously for up to three days in groups of 4 mice. This was performed in the valproic acid (VPA) mouse model where VPA (450 mg/kg) was injected to pregnant females at E12.5. Studies were performed with a special focus on females given that ASD is 3-4 times more diagnosed in males than in females and that several ASD models failed to detect major social deficits in females, contrary to males. Comparisons were made within groups of 4 female animals with same treatment or within groups of different treatments (saline versus VPA). We report that VPA females show several types of social deficits and that are different in nature and magnitude in relation with time (from 1 hour to 3 days). These deficits were also different when VPA mice were tested together compared to when they were mixed with saline treated mice. Indeed, while social behavior was improved in VPA mice with the presence of saline mice that of saline mice was negatively affected by the presence of VPA mice. This study indicates that female VPA mice show several social deficits, contrary to the common knowledge. It further implies that ASD related behavior alters normal behavior in a mixed group of mice.