Assessing Olfaction Using Ultrasonic Vocalization Recordings in Mouse Pups with a Sono-olfactometer

TL;DR

This study introduces a sono-olfactometer to quantify olfactory function in mouse pups by measuring ultrasonic vocalizations in response to odorants, aiding in detecting olfactory deficits due to infections or lesions.

Contribution

The paper presents a novel behavioral test device that precisely measures olfactory-driven ultrasonic vocalizations in mouse pups, useful for assessing olfactory impairments.

Findings

USV are inhibited by specific olfactory cues

The protocol effectively detects olfactory deficits

The method can be applied to pups with altered olfactory systems

Abstract

Olfaction is the first sensory modality to develop during fetal life in mammals, and plays a key role in the various behaviors of neonates such as feeding and social interaction. Odorant cues (i.e., mother or predator scents) can trigger potentiation or inhibition of ultrasonic vocalizations (USV) emitted by pups following their isolation. Here, we report how USV are inhibited by olfactory cues using a sono-olfactometer that has been designed to quantify precisely olfaction in pups congenitally infected by cytomegalovirus. This olfactory-driven behavioral test assesses the USV emitted in presence of unfamiliar odorants such as citral scent or adult male mouse scent. We measure the number of USV emitted as an index of odorant detection during the three periods of the 5-min isolation time of the pup into the sono-olfactometer: first period without any odorant, second period with odorant exposure and last period with exhaust odorant. This protocol can be easily used to reveal olfactory deficits in pups with altered olfactory system due to toxic lesions or infectious diseases.