Mouse vocal emission and acoustic complexity do not scale linearly with the size of a social group

Abstract

Adult mice emit ultrasonic vocalizations (USVs), sounds above the range of human hearing, during social encounters. While mice alter their vocal emissions between isolated and social contexts, technological impediments have hampered our ability to assess how individual mice vocalize in group social settings. We overcame this challenge by implementing an 8-channel microphone array system, allowing us to determine which mouse emitted individual vocalizations across multiple social contexts. This technology, in conjunction with a new approach for extracting and categorizing a complex, full repertoire of vocalizations, facilitated our ability to directly compare how mice modulate their vocal emissions between isolated, dyadic and group social environments. When comparing vocal emission during isolated and social settings, we found that socializing male mice increase the proportion of vocalizations with turning points in frequency modulation and instantaneous jumps in frequency. Moreover, males change the types of vocalizations emitted between social and isolated contexts. In contrast, there was no difference in male vocal emission between dyadic and group social contexts. Female vocal emission, while predominantly absent in isolation, was also similar during dyadic and group interactions. In particular, there were no differences in the proportion of vocalizations with frequency jumps or turning points. Taken together, the findings lay the groundwork necessary for elucidating the stimuli underlying specific features of vocal emission in mice.

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

“…In the vast majority of previous studies investigating mouse social communication, USVs were triggered by social deprivation (e.g., 2 weeks of isolation) and recorded in the first minutes or hours of interaction (Scattoni et al, 2011 ; Neunuebel et al, 2015 ; Warren et al, 2018a , 2020 ; Sangiamo et al, 2020 ). The USV types were either classified in a pre-determined repertoire (Scattoni et al, 2011 ) or simplified for modeling to reduce the complexity of the signals (e.g., ignoring harmonic components or frequency jumps or normalizing over duration; (Neunuebel et al, 2015 ; Warren et al, 2018a , 2020 ; Sangiamo et al, 2020 ; but see Warren et al, 2021 ). In our study, we provide a complementary approach by determining a large set of acoustic variables to avoid masking the complexity of the signals and leave the door open for any user to design their own classification as in Kikusui et al ( 2021 ).…”

Rodent ultrasonic vocal interaction resolved with millimeter precision using hybrid beamforming

“…interaction of more mice as in some of the previous studies. 34,88 (which was not certified by peer review) is the author/funder. All rights reserved.…”

“…USVs have been extensively studied in mice, where their communicative significance has been widely demonstrated by their influence on conspecific behavior [15][16][17][18][19][20] (also in line with observational studies [21][22][23][24] ). USVs can be grouped into different types that are highly context-dependent 17,18,22,[25][26][27][28][29][30][31][32][33][34][35][36][37] , and USV syntax itself is predictive of USV sequence. 38 Taken together, the current literature suggests USVs convey affective and social information in different behavioral contexts.…”

Rates but not acoustic features of ultrasonic vocalizations are related to non-vocal behaviors in mouse pups

“…4A-C). While most previous studies have considered USV acoustic variability by placing USVs into categories defined either by the experimenter or with the help of machine learning (Burkett et al, 2015; Coffey et al, 2019; Fonseca et al, 2021; Holy & Guo, 2005; Van Segbroeck et al, 2017; Vogel et al, 2019, 2019; Warren et al, 2021). Our findings with AVA further support the conclusion that mouse pups do not produce acoustically distinct types of USVs during different categories of non-vocal behaviors (Fig.…”