P. C. CURTIN, M. MAZZELLA, K. A. COX, J. SUTPHEN, D. HOWLAND, T. VOGT, D. BRUNNER
To investigate possible differences in ultrasonic vocalization frequency and structure in a social setting, we recorded behavior and vocalizations by 9-week old wild-type (WT) or zQ175 heterozygous male mice paired with WT females in PhenoCube. In this system we are able to follow behavior day and night and to simultaneously record all vocalizations. Our analysis suggests that the sequential organization of USVs differs in zQ175-WT interactions compared to WT-WT interactions. Further, in both WT-WT and zQ175-WT pairs, there were significant differences in the overall number of vocalizations in day relative to night, in addition to circadian differences in the acoustic parameters of USVs, including amplitude and duration,with USVs being shorter and quieter during the day than at night. This study suggests that, at a very early age, aspects of social behavior may be particularly sensitive to the effect of CAG expansion.