LMT USV Toolbox, a Novel Methodological Approach to Place Mouse Ultrasonic Vocalizations in Their Behavioral Contexts-A Study in Female and Male C57BL/6J Mice and in Shank3 Mutant Females.

Fabrice De Chaumont,Nathalie Lemière,Sabrina Coqueran,Thomas Bourgeron,Elodie Ey

doi:10.3389/fnbeh.2021.735920

Abstract

Ultrasonic vocalizations (USVs) are used as a phenotypic marker in mouse models of neuropsychiatric disorders. Nevertheless, current methodologies still require time-consuming manual input or sound recordings clean of any background noise. We developed a method to overcome these two restraints to boost knowledge on mouse USVs. The methods are freely available and the USV analysis runs online at https://usv.pasteur.cloud. As little is currently known about usage and structure of ultrasonic vocalizations during social interactions over the long-term and in unconstrained context, we investigated mouse spontaneous communication by coupling the analysis of USVs with automatic labeling of behaviors. We continuously recorded during 3 days undisturbed interactions of same-sex pairs of C57BL/6J sexually naive males and females at 5 weeks and 3 and 7 months of age. In same-sex interactions, we observed robust differences between males and females in the amount of USVs produced, in the acoustic structure and in the contexts of emission. The context-specific acoustic variations emerged with increasing age. The emission of USVs also reflected a high level of excitement during social interactions. We finally highlighted the importance of studying long-term spontaneous communication by investigating female mice lacking Shank3, a synaptic protein associated with autism. While the previous short-time constrained investigations could not detect USV emission abnormalities, our analysis revealed robust differences in the usage and structure of the USVs emitted by mutant mice compared to wild-type female pairs.

Highlights

Social communication regulates major biological functions under strong selective pressure, such as finding reproductive partners, raising progeny, group coordination for territory advertisement, and protection from predators (Bradbury and Vehrencamp, 2011)
We developed a method using the Live Mouse Tracker (LMT; de Chaumont et al, 2019), which allows a detailed description of the behavior, synchronized with Ultrasonic vocalizations (USVs) recordings (Figures 1A,B)
We focused on a single age class (3 months of age) since it is the classical age for behavioral characterization

Summary

Introduction

Social communication regulates major biological functions under strong selective pressure, such as finding reproductive partners, raising progeny, group coordination for territory advertisement, and protection from predators (Bradbury and Vehrencamp, 2011) It is not yet clear whether the mechanisms underlying these functions are shared between species, but an increasing number of genes and brain circuits related to social interaction and communication have been identified. Several genes associated with autism have been mutated in animal models and lead to atypical social interactions (e.g., mice: Ey et al, 2011; Crawley, 2012; rats: Modi et al, 2018; Drosophila: Coll-Tané et al, 2019; monkeys: Tu et al, 2019) This suggests that animals can be used as models to better understand the causes of neuropsychiatric conditions affecting social interactions and communication, keeping in mind their limits (e.g., the absence of convincing proofs of vocal learning, a major characteristic of human communication, in the above-cited model species; Jarvis, 2019). We will focus on mice, due to their broad use as models for neuropsychiatric disorders

Methods

Results

Conclusion