Reduced scent marking and ultrasonic vocalizations in the BTBR T plus tf/J mouse model of autism

Qualitative impairments in communication, such as delayed language and poor interactive communication skills, are fundamental to the diagnosis of autism. Investigations into social communication in adult BTBR T+tf/J (BTBR) mice are needed to determine whether this inbred strain incorporates phenotypes relevant to the second diagnostic symptom of autism, communication deficits, along with its strong behavioral phenotypes relevant to the first and third diagnostic symptoms, impairments in social interactions and high levels of repetitive behavior. The aim of the present study was to simultaneously measure female urine-elicited scent marking and ultrasonic vocalizations in adult male BTBR mice, in comparison with a standard control strain with high sociability, C57BL/6J (B6), for the assessment of a potential communication deficit in BTBR. Adult male BTBR mice displayed lower scent marking and minimal ultrasonic vocalization responses to female urine obtained from both B6 and BTBR females. Lower scent marking and ultrasonic vocalizations in a social setting by BTBR, as compared with B6, are consistent with the well-replicated social deficits in this inbred mouse strain. Our findings support the interpretation that BTBR incorporate communication deficits, and suggest that scent marking and ultrasonic vocalizations offer promising measures of interest in social cues that may be widely applicable to investigations of mouse models of autism.