Not all noise is created equal. According to a new study, a background of white noise can enhance how well you hear other sounds. These findings could be used to design new and improved cochlear implants that provide better hearing.
Hearing is an incredibly complex process in which numerous very fragile components of the ear work in unison to pick up pressure waves (i.e. what we call ‘sound’) and relay signals to the brain.
Scientists still don’t understand the complete picture of how acoustic signals are perceived and processed in the brain. But, if there’s one thing we do know about hearing, it’s that the more precisely we can distinguish sounds, the better our hearing. Imagine talking to a person in a crowded bar versus a quiet restaurant. You’d probably have to bend your ear closer to the other person in the former situation to make sense of the conversion, while in the latter scenario you can comfortably understand and communicate with your conversation partner.
Dr. Tania Rinaldi Barkat, a neuroscientist at the University of Basel in Switzerland, wanted to investigate how sound discrimination looks at the neural-level in a challenging sound environment.
The closer two sounds are in their frequency spectrum, the harder it is to tell them apart. You’d also think that having noise in the background would make the task even more challenging — but the opposite was true in measurements of a mouse brain.
Barkat and colleagues showed that when white noise was in the background, the brain’s ability to distinguish subtle tone differences improved compared to a quiet environment. In other words, the noise facilitated rather than hindered auditory perception.
When they focused on the matter, the researchers found that white noise can inhibit the activity of nerve cells in the auditory cortex, which is the area of the brain that is most involved in processing acoustic signals. But this suppression ironically led to a better auditory perception of the pure tones.
“We found that less overlap occurred between populations of neurons during two separate tone representations,” explains Professor Tania Barkat. “As a result, the overall reduction in neuronal activity produced a more distinct tone representation.”
This new insight could be used to improve hearing aids, which could stimulate users with a mild white noise in order to improve auditory discrimination.