Throughout the animal kingdom, social interaction is fundamental for survival and reproduction. Such behavior consists of dynamic, complex interactions between animals and can promote cooperation or competition within the group. Vocalizations, in particular, play a substantial role in group dynamics — by warning group members of specific predators, or indicating that reproductive opportunities exist. From past experience of these GEITP pages, while working in the mouse facilities late into the night, we were often convinced that the various squeaks emitted by those creatures were actually their little voices saying nasty things about us, and likely proposing a massive uprising. ☹
Substantial advances in understanding the neurobiology of social behavior, as well as complex social network dynamics, have been made — using mice as a model system — because mice are social animals that engage in diverse behaviors accompanied by ultrasonic vocalizations (USVs). [USVs are auditory signals spanning a range of 35 to 110 kHz.] Mice readily approach and investigate the source of USVs, and female mice prefer to spend time near a vocalizing male, rather than a mute male [the same is true in humans]. Together, these measures used to quantify mouse behavior imply that USVs are relevant to the dynamics underlying social interactions.
USVs show a diverse acoustic profile, suggesting that multiple categories or types of vocalizations exist. The types of USVs that mice produce vary with recording conditions or context, genetic differences, and an animal’s developmental stage (i.e. age). Although several variables appear to influence the types of vocalizations produced, the extent to which mouse vocalizations influence social dynamics is unknown. Therefore, by combining a sound-source localization system to track vocal activity of individual adult mice — with a machine-learning algorithm to automatically detect specific social behaviors, and with a vocalization-clustering program to group similarly shaped vocal signals — authors [see attached article] were able to associate different types of USVs with distinct behaviors of the vocalizing mouse.
They demonstrated that specific patterns of vocalization influence the behavior of only the socially engaged partner. Authors showed that distinct patterns of vocalization emerge as male mice perform specific social actions (mice dominating other mice were more likely to emit different vocal signals than mice avoiding social interactions). Furthermore, it was shown that patterns of vocal expression influence behavior of the socially engaged partner, but do not influence the behavior of other animals in the cage. These findings clarify the function of mouse communication by revealing a communicative ultrasonic-signaling repertoire. This approach could help elucidate the role that communication plays in social dynamics — thus paving the way to a mechanistic understanding of the neural basis of social behavior. 😊
Nature Neurosci http://doi.org/dm6g (2020)