How the Brain Localizes Sound

Posted by John Farrier in Science & Tech on August 31, 2009 at 2:11 pm

With sound sources bouncing off walls and other surfaces, how is the brain able to sort out from what direction and distance sound is traveling? Robert Goodier explains:

In an April study, neuroscientists led by Sasha Devore at the Massachusetts Institute of Technology tested the widely held hypothesis that specialized cells in the brain actively suppress neuronal response to echoes. Using electrodes in a cat’s midbrain, researchers measured cells’ responses to a sound and its reverberations. They found that the cells that sense a sound’s direction of origin responded more strongly to the first 50 milliseconds of sound waves than they did to the later waves—their activity simply tapered off after the onset of the sound. The tapering response, a much simpler mechanism than the earlier theory of suppression, allows the brain to easily tune in to original sounds and pinpoint who or what is making noise.

Link

Image by flickr user mystical child used under creative commons license

 
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The Teenager Audio Test

Posted by Miss Cellania in Everything Else on February 26, 2009 at 11:21 am

Train Horns

Can you hear the sound in the clip at this site? I can’t, but that’s not surprising. It can generally only be heard by people under the age of 25. Those who can hear it say it’s pretty annoying. Some older folks use it to repel teens, but some young people use it for a ring tone. Link -via Digg

 
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Kiss Kills Woman's Hearing

Posted by Jill Harness in Everything Else, Odd News on December 13, 2008 at 4:22 pm

A 20-something woman in China recently had her left ear drum blown out by a massive kiss. She has become partially deaf as a result of the passionate kiss.

Chinese media companies are now spreading warnings about the dangers of kissing. It seems it is pretty easy for any kiss to blow out an ear drum because pressure can be imbalanced between the two ears, which can lead to one of the drums breaking.

Link Photo via Bob.Fornal [Flickr]

 
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