High-precision spatial analysis of mouse courtship vocalization behavior reveals sex and strain differences.

Mice display a wide repertoire of vocalizations that varies with sex, strain, and context. Especially during social interaction, including sexually motivated dyadic interaction, mice emit sequences of ultrasonic vocalizations (USVs) of high complexity. As animals of both sexes vocalize, a reliable attribution of USVs to their emitter is essential. The state-of-the-art in sound localization for USVs in 2D allows spatial localization at a resolution of multiple centimeters. However, animals interact at closer ranges, e.g. snout-to-snout. Hence, improved algorithms are required to reliably assign USVs. We present a novel algorithm, SLIM (Sound Localization via Intersecting Manifolds), that achieves a 2-3-fold improvement in accuracy (13.1-14.3 mm) using only 4 microphones and extends to many microphones and localization in 3D. This accuracy allows reliable assignment of 84.3% of all USVs in our dataset. We apply SLIM to courtship interactions between adult C57Bl/6J wildtype mice and those carrying a heterozygous Foxp2 variant (R552H). The improved spatial accuracy reveals that vocalization behavior is dependent on the spatial relation between the interacting mice. Female mice vocalized more in close snout-to-snout interaction while male mice vocalized more when the male snout was in close proximity to the female's ano-genital region. Further, we find that the acoustic properties of the ultrasonic vocalizations (duration, Wiener Entropy, and sound level) are dependent on the spatial relation between the interacting mice as well as on the genotype. In conclusion, the improved attribution of vocalizations to their emitters provides a foundation for better understanding social vocal behaviors.

Mitigating medical student stress and anxiety: Should schools mandate participation in wellness intervention programs?

PURPOSE: Medical students are at increased risk of poor mental health and need to regularly engage in preventive programs to maintain well-being. However, many do not and it remains an open question whether these programs should be mandatory. We implemented a RCT to examine the effectiveness of assigning medical students to a wellness intervention on adherence to engagement in the assigned intervention and on psychological and academic outcomes. METHOD: Medical students participated in a 12-week randomized controlled intervention involving one-hour wellness sessions of either (1) yoga; (2) mindfulness; or (3) walking, held twice-weekly. Students completed standardized psychological assessments at baseline and following the intervention. RESULTS: Students randomized to the wellness intervention group engaged in more minutes of assigned activities than students randomized to the control. There was a significant difference in the change from pre- to post- intervention on measures of state anxiety and perceived stress, with better outcomes for the intervention group. CONCLUSIONS: The assignment of twice-weekly wellness intervention sessions protects medical students from state anxiety and perceived stress with no negative impact on academic performance. Students adhered to the sessions and reported enjoying the sessions once trying them. Actual engagement is more important than wellness activity type.