Brain’s special sound skill
BY wangxingwei from 21st Century
Published 2019-01-31
Our brain is able to ignore our own footsteps, according to a new study. CFP

You’re walking down a quiet street and suddenly you hear some footsteps. Undoubtedly, it means that there’s someone around. But have you ever wondered why it occurs to us that it’s someone else’s footsteps, not ours?

According to a new study published in the journal Nature in September, this phenomenon results from a function in our brain to ignore the noises we make ourselves.
据去年9月发布于《自然》期刊的一项新研究表明,这一现象源于大脑的一项功能 —— 忽略我们自身发出的声音。

In order to explore how our brain does this, a group of scientists from New York University in the US carried out an experiment with mice at Duke University. In the experiment, researchers controlled the sounds a group of mice could hear, reported Science Daily.

During the first several days, the mice would hear the same sound each time they took a step. This was just like “running on a tiny piano with each key playing exactly the same note”, senior study author Richard Mooney, a professor of neurobiology at Duke University, told Live Science.

Scientists found that their auditory cortex – the area of the brain that processes sound – became active at first but decreased its response to the sound after two or three minutes when the mice became familiar with it.
科学家们发现,老鼠的听觉皮层 —— 大脑处理声音的区域 —— 刚开始的时候十分活跃,但过了两三分钟,老鼠对声音熟悉了之后,它们的听觉皮层对声音的反应便降低了。

“It’s almost like they were wearing special headphones that could filter out the sound of their own movements,” David Schneider, an assistant professor at the Center for Neural Science at New York University, told HuffPost.

But once the sound changed, their auditory cortex became active again.

This suggests that the “sensory filter” in a mouse’s brain could help it detect new sounds or abnormal noise in the environment easily after tuning out familiar sounds, according to Science Daily.

“For mice, this is really important,” said Schneider. “They are prey animals, so they really need to be able to listen for a cat creeping up on them, even when they’re walking and making noise.”

As important as it is for mice’s survival, the ability to ignore movement-related noises is also useful for humans when it comes to complex tasks, such as playing an instrument.

According to Schneider, “the ability to ignore the expected consequences of our movement gives us the extra-cool ability to detect when we’ve got it wrong. So if I play the piano just right, I hear it, but my auditory cortex is pretty silent. But when I play it wrong, I get a much larger response.”

So, our brain could be telling us, “Hey, that didn’t sound right, maybe I should move my fingers a little different next time,” Schneider told HuffPost.

(Translator & Editor: Wang Xingwei AND Luo Sitian)
Auditory cortex  听觉皮层
Filter out  过滤掉
Sensory  感觉的
Detect  察觉
Abnormal  反常的
Prey  猎物