Air Date: Week of October 29, 2004

Living on Earth’s Jennifer Chu reports on a new discovery that explains how we translate sound waves to the brain.

Transcript

CURWOOD: Just ahead: a field guide to sprawl. First, this Note on Emerging Science from Jennifer Chu.

[SCIENCE NOTE THEME]

CHU: Now hear this!

For years, scientists have puzzled over how sound waves flow through the ear and transform into electrical impulses that can be interpreted by the brain. In other words, how is it we can translate thousands of unique air vibrations into distinguishable sounds, such as the words in this report and the music you hear in the background?

Researchers at the University of Virginia say they’ve taken the “mute” button off this mystery. In an article posted on the Internet edition of the journal Nature, the scientists report that they have identified a doughnut-shaped protein located at the tips of sensory hairs in the inner ear that’s key to our ability to hear.

In the absence of sound, this doughnut hole is closed. But when sound strikes the protein, the hole pops open and allows potassium and calcium ions to flood the cells of the sensory hairs. The ions carry a positive electrical charge which generates an electrical signal inside the cells. This signal is then relayed to the brain and interpreted as specific sounds. Researchers hope the discovery could lead to new therapies for certain types of deafness in the next ten years.

That’s this week’s Note on Emerging Science. I’m Jennifer Chu.

CURWOOD: And you’re listening to NPR’s Living on Earth.

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[MUSIC: Ry Cooder “Cancion Mixteca” PARIS, TEXAS ORIGINAL MOTION PICTURE SOUNDTRACK (Warner Brothers – 1985)]