Featured Research

from universities, journals, and other organizations

Hopkins Scientists Reveal How Sound Becomes Electric

Date:
May 3, 2002
Source:
Johns Hopkins Medical Institutions
Summary:
Scientists from The Center for Hearing and Balance at Johns Hopkins have discovered how tiny cells in the inner ear change sound into an electrical signal the brain can understand.

Scientists from The Center for Hearing and Balance at Johns Hopkins have discovered how tiny cells in the inner ear change sound into an electrical signal the brain can understand.

Their finding, published in a recent issue of Nature Neuroscience, could improve the design and programming of hearing aids and cochlear implants by filling in a "black hole" in scientists' understanding of how we hear, say the researchers.

"Sound itself is mechanical, a wave that moves, just like the ripples fanning out from a pebble dropped in a lake," says Paul Fuchs, Ph.D., professor of otolaryngology at the Johns Hopkins School of Medicine. "When the inner ear detects this wave, a burst of chemicals is released and a nerve sends an electrical signal to the brain that carries information about the original sound. But the nature of the chemical burst has been a mystery until now."

With the help of powerful microscopes, the scientists studied individual cells from rat cochleas, tiny coiled structures deep inside the ear where sound is translated into electricity, the language of the brain. Fuchs and research associate Elisabeth Glowatzki discovered that these so-called "hair cells," named for tiny projections that stick up like a spiky haircut, release a barrage of chemical packets to an adjacent nerve in response to sound.

The finding was unexpected, Fuchs says, because hair cells were thought previously only to communicate to nerves by sending a single packet of these chemical transmitters at a time.

"Most cells in the brain normally move one packet to their edges, releasing a single dollop of transmitter that travels the short distance to the nerve," he says. "But hair cells deliver a dramatic burst of packets."

The scientists suggest this means of communication with nerves may help hair cells carefully control the signals they send. "Hearing requires smooth signaling to accurately detect and distinguish a wide range of sound frequency (pitch) and intensity (volume)," Fuchs says.

"Nerves connecting to other cells have to collect the chemical messengers for awhile before they will send an electrical signal to the brain; those nerves have to reach a threshold level of stimulation. And once the signal is sent, the nerve is quiet again," adds Fuchs. "But for hair cells, their continual pumping of messengers toward the nerve may be a kind of fail-safe device that ensures a ready supply of transmitters should the sound continue or change."

Hearing aids and cochlear implants are designed to boost or replace the sound-detecting function of hair cells in the cochlea. Fuchs and Glowatzki believe their discovery might help improve the range or accuracy of hearing aids and cochlear implants, they say.

The studies were funded by the U.S. National Institute on Deafness and Other Communication Disorders, one of the National Institutes of Health.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "Hopkins Scientists Reveal How Sound Becomes Electric." ScienceDaily. ScienceDaily, 3 May 2002. <www.sciencedaily.com/releases/2002/05/020503075233.htm>.
Johns Hopkins Medical Institutions. (2002, May 3). Hopkins Scientists Reveal How Sound Becomes Electric. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2002/05/020503075233.htm
Johns Hopkins Medical Institutions. "Hopkins Scientists Reveal How Sound Becomes Electric." ScienceDaily. www.sciencedaily.com/releases/2002/05/020503075233.htm (accessed September 18, 2014).

Share This



More Health & Medicine News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Artificial Sweetener Could Promote Diabetes

Artificial Sweetener Could Promote Diabetes

Newsy (Sep. 17, 2014) Doctors once thought artificial sweeteners lacked the health risks of sugar, but a new study says they can impact blood sugar levels the same way. Video provided by Newsy
Powered by NewsLook.com
Ebola Vaccine Trial Gets Underway at Oxford University

Ebola Vaccine Trial Gets Underway at Oxford University

AFP (Sep. 17, 2014) A healthy British volunteer is to become the first person to receive a new vaccine for the Ebola virus after US President Barack Obama called for action against the epidemic and warned it was "spiralling out of control." Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
Obesity Rates Steady Even As Americans' Waistlines Expand

Obesity Rates Steady Even As Americans' Waistlines Expand

Newsy (Sep. 17, 2014) Researchers are puzzled as to why obesity rates remain relatively stable as average waistlines continue to expand. Video provided by Newsy
Powered by NewsLook.com
President To Send 3,000 Military Personnel To Fight Ebola

President To Send 3,000 Military Personnel To Fight Ebola

Newsy (Sep. 16, 2014) President Obama is expected to send 3,000 troops to West Africa as part of the effort to contain Ebola's spread. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins