Social Ultrasonic Vocalization in Awake Head-Restrained Mouse

Abstract

Numerous animal species emit vocalizations in response to various social stimuli. The neural basis of vocal communication has been investigated in monkeys, songbirds, rats, bats, and invertebrates resulting in deep insights into motor control, neural coding, and learning. Mice, which recently became very popular as a model system for mammalian neuroscience, also utilize ultrasonic vocalizations (USVs) during mating behavior. However, our knowledge is lacking of both the behavior and its underlying neural mechanism. We developed a novel method for head-restrained male mice (HRMM) to interact with non-restrained female mice (NRFM) and show that mice can emit USVs in this context. We first recorded USVs in a free arena with non-restrained male mice (NRMM) and NRFM. Of the NRMM, which vocalized in the free arena, the majority could be habituated to also vocalize while head-restrained but only when a female mouse was present in proximity. The USVs emitted by HRMM are similar to the USVs of NRMM in the presence of a female mouse in their spectral structure, inter-syllable interval distribution, and USV sequence length, and therefore are interpreted as social USVs. By analyzing the vocalizations of NRMM, we established criteria to predict which individuals are likely to vocalize while head fixed based on the USV rate and average syllable duration. To characterize the USVs emitted by HRMM, we analyzed the syllable composition of HRMM and NRMM and found that USVs emitted by HRMM have a higher proportion of USVs with complex spectral representation, supporting previous studies showing that mice social USVs are context dependent. Our results suggest a way to study the neural mechanisms of production and control of social vocalization in mice using advanced methods requiring head fixation.

Dorsal Raphe Dopamine Neurons Signal Motivational Salience Dependent on Internal State, Expectation, and Behavioral Context

“…Head-fixation is widely used in imaging and behavioral experiments due to the need for mechanical stability or convenience, but the effects on animal behavior or neural activity are often assumed to be negligible. However, in rodents, head-fixation affects vocalization behavior (Weiner et al, 2016). At the neural level, acute head restraint reduces the reward and cue responses of VTA DA and DRN serotonergic neurons (Zhong et al, 2017).…”

Rapid development of mature vocal patterns of ultrasonic calls in a fast-growing rodent, the yellow steppe lemming (Eolagurus luteus)

“…This makes the yellow steppe lemming a very convenient cross-age and cross-sex animal model of USV ontogeny. At the same time, for the mice model, the isolation procedure is inapplicable for all ages because of a low USV call rate at older ages [10,125]. Although the isolation-induced USV calls reported not only for pup but also for adult mice [5,125], for most individual adolescent and adult mice the isolation or restraint procedure is ineffective for inducing the USV calls and some kind of social stimulation from conspecifics is necessary to provoke the ultrasonic vocalization [10,37,[125][126][127][128][129][130].…”

“…The alternative longitudinal approach, using the same individuals repeatedly tested in different ages, allows tracking the ontogenetic changes at individual level [39,131]. However, the longitudinal approach does not avoid potential effects of habituation to test procedure on vocal and physical development of study animals [125,130,141,142]. The use of the cross-sectional approach with many non-overlapping age classes (age-class slicing) allows avoiding the potential effects of habituation to test procedure and at the same time enables to track the ontogenetic changes along the entire development, thus combining the advantages of both the cross-sectional and longitudinal approaches.…”

Dorsal raphe dopamine neurons signal motivational salience dependent on internal and external states

“…Head-fixation is widely used in imaging and behavioral experiments due to the need for mechanical stability or convenience, but the effects on behavior or neural activity are often assumed to be negligible. However, in rodents, headfixation affects vocalization behavior (Weiner et al, 2016), and acute head restraint reduces the reward and cue responses of VTA DA and DRN serotonergic neurons (Zhong et al, 2017). Head-fixed mice showed higher corticosterone level over control subjects, even up to 25 days of daily training (Juczewski et al, 2020).…”