Protein Key to Human Hearing Discovered

A single 'hair cell bundle' located in the inner ear. i i

An electron micrograph image shows a single "hair cell bundle" located in the inner ear. There are 17,000 of these hair cells in each ear that detect and amplify sound waves. The newly detected protein, called TRPA1, sits at the tips of these structures. David Furness, Carole Hackney, Keele University, U.K. hide caption

itoggle caption David Furness, Carole Hackney, Keele University, U.K.
A single 'hair cell bundle' located in the inner ear.

An electron micrograph image shows a single "hair cell bundle" located in the inner ear. There are 17,000 of these hair cells in each ear that detect and amplify sound waves. The newly detected protein, called TRPA1, sits at the tips of these structures.

David Furness, Carole Hackney, Keele University, U.K.
Professor David Corey of Harvard Medical School

Professor David Corey of Harvard Medical School led the research team that identified a protein key to human hearing. Richard Knox, NPR hide caption

itoggle caption Richard Knox, NPR

Scientists at Harvard Medical School and elsewhere have found the long-sought protein that transforms sound waves into nerve impulses. As NPR's Richard Knox reports, researchers are learning that hearing is the "fastest" of the senses — faster even than vision in the way that the newly discovered protein transforms input into nerve signals.

How TRPA1 Works

A donut-shaped molecule, TRPA1 snaps open when a sound wave of a particular frequency sweeps past. This allows electrically charged ions of potassium to flow into the hair cell, generating an electrical impulse that travels along a nerve cell to the brain. The system is designed to work incredibly fast.

Our sense of hearing needs to be fast — not only to warn us of danger and the direction it's coming from, but also to enable us to perceive the incredible density of information —- tone, pitch, volume and the rapidly changing stream of vowels and consonants — in speech.

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