From closing car doors to kicking a soccer ball to composing music, the brain knows how to tell ‘right’ from ‘wrong’ – ScienceDaily

Whether it’s an improperly closed car door, a kick in soccer, or an incorrect note in music, our ears tell us when something doesn’t sound right. A team of neuroscientists recently revealed how the brain works to distinguish between “correct” and “wrong” sounds, research that provides a deeper understanding of how we learn complex audio-motor tasks such as speaking or playing music.

“We listen to the sounds our movements make to determine whether we’ve made a mistake or not,” said David Schneider, an assistant professor at New York University’s Center for Neural Sciences and senior author of the paper, which appears in the journal Current Biology. “This is most obvious for a musician or when speaking, but our brains actually do this all the time, such as when a golfer listens for the sound of his club making contact with the ball. Our brains are always registering whether a sound matches or deviates from expectations. In our study, we found that the brain is able to make accurate predictions about when a sound should occur and how it should sound.”

Researchers have focused their work on better understanding everyday phenomena. For example, we know what a car door should sound like because we’ve closed it countless times. However, in cases where we leave the seat belt in the door frame of the car and try to close it, we hear something different – a “cling” and not a “thump”. It’s the same with a baseball player who hits a pitched ball straight instead of just pitching it—or when a musician hears a note that fits the melody rather than one that breaks it.

However, it is not clear how the brain works to distinguish “right” from “wrong” sounds. Understanding how this is done could offer insights into how the healthy brain can learn to speak and play music, and what goes wrong in neural disorders such as schizophrenia.

To address this, Schneider and his colleagues examined the neurological activity of mice when they performed tasks similar to closing a car door. The scientists trained mice to press a lever with their paws — like closing a car door — and played a tone every time the lever reached a certain position. Eventually, the mice learned exactly what the lever should sound like. If the researchers removed the sound, played the wrong sound, or played the right sound at the wrong time, the mice corrected their behavior, just as humans would if a car door did something unexpected.

The scientists recorded the mice’s brain activity during these behaviors — specifically how neurons responded in the auditory cortex, one of the brain’s “hearing centers.” Overall, these neurons were minimally active when the mouse pressed a lever and heard expected sound. However, if the researchers change the sound to the wrong frequency—similar to the “rattling” of a car door—or even slightly shift synchronization to the sound, these neurons responded vigorously.

“The auditory cortex doesn’t seem to signal What was heard, but whether what was heard matched or violated his expectations,” notes Nicolas Audet, the study’s lead author and a postdoctoral fellow in Schneider’s lab.

In addition, the researchers found that if they missed the sound completely—similar to not closing a door hard enough—they observed a select group of neurons activate during the sound. there should be happened.

“Because these were some of the same neurons that would have been active if the sound had actually been played, it was as if the brain was recalling a memory of the sound it thought it was going to hear,” notes Schneider.

In addition to its role in predicting self-generated sounds during everyday behavior, the same brain circuit that Schneider and his colleagues studied is thought to malfunction in diseases such as schizophrenia, leading to the perception of “phantom voices” that they’re not actually there. Their hope is that by understanding these brain circuits in the healthy brain, they can begin to understand what can go wrong during disease.

The other authors of the study are Alessandro La Chioma, a postdoctoral fellow at the Center for Neural Sciences, and Wenxi Zhou, a postdoctoral fellow at New York University.

This research was supported by grants from the National Institutes of Health (T32-MH019524, 1R01-DC018802).

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