Here's how your brain knows when things don't sound normal - study

Humans may have parts of our brains that specifically respond only when something happens differently from how we expected based on sounds, a new study found.

The study was originally published in the peer-reviewed science journal JNeurosci on October 25, 2023, and was sponsored by the National Institutes of Health.

The researchers, a team of neuroscientists from New York University, located a group of neurons in the brain that do not respond when hearing sounds but rather only if the sound heard is not the sound anticipated thus sending a message that something unusual has occurred.

“Brains are remarkable at detecting what’s happening in the world, but they are even better at telling you whether what happened was expected or not. We found that there are specific neurons in the brain that don't tell you what happened, but instead tell you what went wrong,” David Schneider, the study’s lead author and an assistant professor at the university elucidated.

The scientists are hoping that this new information could be valuable in treating certain illnesses and selecting individuals with unique sound-related skills.

Learning to play musical instruments

“Neurons like these might be vital in learning how to speak or how to play a musical instrument,” observes Nicholas Audette, a postdoctoral fellow in NYU’s Center for Neural Science and the paper’s lead author. “Both of those behaviors involve lots of trial and error, lots of mistakes, and lots of learning from mistakes.”Schneider added, “Do expert musicians have better prediction error neurons than novices? And in diseases in which speech is underdeveloped, are prediction error neurons malfunctioning?”

The study used mice that were trained to hear a specific sound at specific times. The researchers then changed the volume of the sound or even when exactly it occurred. They noticed these unique neurons lighting up, not when the sound was normal, but only when it had been altered.

They noticed that different neurons lit up at different times depending on whether the difference introduced was volume, timing, or other variables. This showed that brains have very specific ways of messaging when something odd has happened and exactly what was unusual.