Listen: Why Can We Hear Others' Footsteps, But Not Our Own?
"Welcome to the future of spaceflight experience. The journey live and stay tuned for the crude rude launch. Featuring Boeing's first commercial commander Chris Ferguson. Welcome to brain stuff. Production of iheartradio. Hey brain stuff. Lauren Vogel bomb here. You're walking down a deserted street to all quiet in your thoughts and suddenly you hear footsteps. Of course your own footfalls were making noise too. So why is it so easy to ignore our own noises and so easy to hear others. Scientists scientists have long known that we're capable of tuning out our own personal noises but we're previously in the dark about how the brain accomplishes this feat. The results of a new study published in the Journal. Channel nature aims to amp up our understanding of this phenomenon by focusing on footsteps. We spoke with lead researcher. Dr David Schneider and Assistant Professor with the Center for Neuroscience at New York University. He explained we wanted to understand how the individual cells and our brains are neurons. Work together to make that happen. I've been to do that. We studied mouse brains and we built an augmented reality system. So that when mice ran we could experimentally. Control the sounds. They heard we. We could give them a couple of days with their walking making one sound then. We could unexpectedly switched the sound. The research was conducted at Duke University School of Medicine. The scientists soon discovered that when the mice expected they're walking to sound a particular way the neurons in the auditory cortex. One of the main hearing centers of the brain stopped responding into the noise. Schneider said it was almost like they were wearing special. Headphones could filter out the sound of their own movements in contrast when we played an unexpected sound neurons and their auditory cortex had large responses. The scientists soon realized that as the mice were becoming familiar with the sounds of their own. Walking there were some important. Connections being changed between the auditory cortex and the motor cortex. which is the part of the brain responsible for moving? Schneider said the connections and strengthen onto inhibitory neurons in the auditory cortex that are active. When the mouse heard the footsteps sound the end result was that every time the mouse walked a group of inhibitory inhibitory neurons were active to create a photo negative of the sound. The mouse expected which could cancel out the expected sound when it was heard. The experience isn't limited to footsteps. Either Schneider said the heavy breather rarely knows that they're heavy breather because it doesn't sound as loud to them and I think the same is true of key strokes folks assure I can hear my own keystroke when I'm typing but I don't usually get annoyed by them but if someone's sitting next to me was typing heavily. Drives me batty for any any creature. Accustomed to being hunted like mice. This ability to filter out one's own innocuous noises and focus on the more potentially dangerous ones is critical. This is also the same phenomenon at play when we sing. Speak or play music. Schneider explained we usually have an idea in our head for what sounded like to produce use when I sit down at piano and strike the keys for example. I know what music I want it to make. But when we're practicing we often get it wrong the mechanism that we've described in this paper. 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 sure but my auditory cortex is pretty silent but when I play it wrong I get a much larger response as a result. The brain is able to interpret Britt that responses. Hey that didn't sound right. Maybe I should move my fingers a little different next time that allows us to learn from our mistakes though. The researchers are still trying to figure out what exactly how such errors signals are employed by the brain when learning language and music"