Summary: Alston’s singing mice produce loud, rhythmic songs that scientists can clearly hear, alongside ultrasonic calls used for close-range communication. Researchers discovered that both types of vocalizations are generated through a whistle-like airflow mechanism rather than vibrating vocal cords.
Surprisingly, the same brain region used for everyday squeaks in ordinary mice also controls both songs and ultrasonic calls in singing mice. These findings reveal how complex vocal behaviors may evolve without requiring entirely new brain circuits, offering clues for understanding speech disorders in humans.
Key Facts
- Whistle-Based Sound Production: Both songs and ultrasonic calls are generated by air flowing through the vocal system.
- Shared Brain Circuit: Singing and squeaking rely on the same core vocal brain region found in typical mice.
- Human Health Relevance: The findings may inform research into speech loss, autism, and AI sound recognition.
Source: CSHL
All mice squeak, but only some sing. Scotinomys teguina, aka Alston’s singing mice, hail from the cloud forests of Costa Rica. More than 2,000 miles north, Cold Spring Harbor Laboratory (CSHL) neuroscientists study these musically gifted mammals to better understand the evolutionary origins of vocal communication.
Their research could also tell us something about strokes, autism, and other disorders affecting speech.
While most of us are familiar with mouse squeaks, “they have a whole other communications system called ultrasonic vocalizations (USVs),” says CSHL Assistant Professor Arkarup Banerjee.
USVs are so high-pitched and soft we can only hear them with special devices. That’s not the case for the “songs” of Alston’s singing mice. Most of us can hear them clearly.
Notably, singing mice can also communicate via USVs. It’s thought that they sing to project across great distances—an important skill for living among the clouds.
But just how are these communications physically produced? How do singing mice’s brains, which are comparable to those of ordinary lab mice, enable such complex behavior?
Banerjee’s latest study, published in Current Biology, addresses both questions.
First, Banerjee and his team developed a behavioral test called PARId to characterize the different sounds that singing mice can make. The tests confirmed Alston’s mice use long, loud, rhythmic songs to communicate from afar and USVs for close talking.
Banerjee lab postdoc Cliff Harpole then gave the mice helium to see if they produced songs by vibrating their vocal cords or blowing air. The “party trick” offered surprising results, Banerjee says.
“For both USVs and songs, the pitch went up. So, we know for sure that they’re produced by a whistle mechanism.”
Next, CSHL grad student Xiaoyue Mike Zheng used special viruses to target certain areas of the mice’s brains. These tests revealed something arguably even more surprising. It turns out Alston’s mice use the same brain region for singing and USVs. And it’s the same region ordinary lab mice use for daily communications.
The finding offers an important clue in the mystery of how mammals’ brains have evolved to enable complex behaviors like social interactions.
“This is one of the foundational studies from the lab trying to get into this new domain of how behaviors evolve,” Banerjee explains. “We have found what is common. So now the hunt is on for what’s different.”
In time, the Banerjee lab’s research on vocal communication could have implications for people with profound autism or stroke-induced aphasia. Their findings may even help engineers make AI better at recognizing specific words and noises. Now, how does that sound?
Key Questions Answered:
A: Alston’s singing mice use a specialized whistle-based vocal mechanism that allows them to produce loud, rhythmic songs for long-distance communication.
A: No—both their songs and ultrasonic calls are controlled by the same core brain region used by ordinary mice for communication.
A: It helps explain how complex vocal communication evolved and may inform future treatments for speech loss after stroke or in autism.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this communication and neuroscience research news
Author: Samuel Diamond
Source: CSHL
Contact: Samuel Diamond – CSHL
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Vocal repertoire expansion in singing mice by co-opting a conserved midbrain circuit node” by Arkarup Banerjee et al. Current Biology
Abstract
Vocal repertoire expansion in singing mice by co-opting a conserved midbrain circuit node
How neural circuits generate diverse behaviors is a fundamental question in neuroscience.
Distinct behavioral outputs may arise from either dedicated motor circuits or shared circuits operating in different functional states.
Although multifunctional circuits offer an efficient solution for behavioral flexibility and may drive rapid evolutionary adaptations, their neural mechanisms remain poorly understood, especially in mammals.
Here, we leverage the rich vocal repertoire of the singing mouse (Scotinomys teguina) to investigate the organizational logic of multifunctional motor circuits.
We developed a behavioral assay (partial acoustic isolation reveals identity [PAIRId]) that enables precise attribution of vocalizations during social interactions.
This paradigm revealed two distinct vocal modes: soft, variable, ultrasonic vocalizations (USVs) ancestral to rodents, used for short-range communication, and loud, rhythmic, human-audible songs unique to the singing mouse lineage, used for long-range communication.
Despite their substantial acoustic and contextual differences, we found that USVs and songs do not arise from parallel pathways. Instead, they share the same sound production mechanism, phonatory-respiratory coupling, and vocal gating from the midbrain caudolateral periaqueductal gray (clPAG).
To understand the mechanism governing song production, we combined mathematical modeling of song rhythm with synaptic silencing of clPAG, which progressively reduced song amplitude and duration.
We demonstrate that song duration decreases via a single parameter controlling its termination.
Notably, this mechanism also accounts for sexual dimorphism in songs, identifying clPAG as a key locus for driving natural behavioral variability.
Our findings reveal how parametric tuning of a central circuit node produces distinct vocal modes, providing a mechanistic basis for rapid behavioral evolution in mammals.
