What Do Mice Hear and How Does It Work? Researchers Study Process with New Imaging Technique

What do mice hear? And how? Getting to the crux of that could help scientists not only learn more about the auditory world of a mouse, but also to help people who need cochlear implants and like devices hear better and lead better lives.

Interestingly, researchers at Johns Hopkins have discovered that perhaps the sound-sensing sectors of the mouse brain don’t work the way previously thought. Results from recent experiments, published in the journal Neuron, suggest that the neat and tidy auditory bands once believed to control sound processing might actually give way to much more diffuse processing mechanisms.

While researchers previously conducted studies of hearing in mice by a process of electrode probing into the animal’s auditory cortex (the area of the brain which processes sound), the latest technique — two-photon microscopy — has given researchers a means of observing minute slices of the active mouse brain, and to study auditory information in heretofore inaccessible detail.

The new methodology has brought new insights. For one, those “manicured auditory lawns” might actually look more like a wild garden.

“You could lose your way within the zoomed-in views afforded by two-photon microscopy and not know exactly where you are in the brain,” explains David Yue, professor of biomedical engineering and neuroscience at the Johns Hopkins University School of Medicine.

New ways of conducting the research and sophisticated imaging technology have led the team to interesting discoveries, including a better understanding of the complex properties of the auditory cortex. In fact, it is helping the scientists more thoroughly map what in fact happens when mice chirp at each other.

“Understanding how sound representation is organized in the brain is ultimately very important for better treating hearing deficits,” Yue said. “We hope that mouse experiments like this can provide a basis for figuring out how our own brains process language.”