- Home
- Diseases and Conditions
- Inner Ear May Harbor Clues to Tinnitus
Inner Ear May Harbor Clues to Tinnitus
- By Caren Jacobs
- Published December 5th, 2008
- Diseases and Conditions
- Unrated
Despite common wisdom that supporting inner-ear cells does not have any kind of connecticity with hearing, still the fact is that they play a very vital role in the development of the fetal "pre-hearing" brain. The theory has been explained by a lot of investigators all this while.
Supporting cells in the organ of Corti, the cochlea that is geared up with auditory sensory hair cells, is responsible for initiating electrical activity in the auditory nerve before the development of hearing, found Dwight E. Bergles, Ph.D., of Johns Hopkins, and colleagues.
According to the studies, it has been suggested that in the developing brain of animals, also if we talk about human beings, the fact is that nonsensory support cells have a vital role to play in the development of central auditory pathways.
This whole research can further explian the development of peripheral tinnitus later in life, the authors wrote in the Nov. 1 issue of Nature.
"It's long been thought that nerve cells that connect auditory organs to the brain need to experience sound or other nerve activity to find their way to the part of the brain responsible for processing sound," Dr. Bergles said. "So when we saw that these supporting cells could generate their
own electrical activity, we suspected they might somehow be involved in triggering the activity required for proper nerve wiring."
"It is as if ATP substitutes for sound when the ear is still immature and physically incapable of detecting sound," said Dr. Bergles. "The cells we have been studying seem to be warming up the machinery that will later be used to transmit sound signals to the brain...We think that only a few cells release ATP at one time, and that a small amount of free-floating ATP then activates only a few nearby hair cells."
The ATP-mediated signaling appears to orchestrate the output that is provided by the neighboring inner hair cells. The fact is that this whole process may provide a big amount of contribution to the mapping of the spatial location of sound perception, reception, or transmission, the authors suggested.
Although the spontaneous release of ATP by the cells stops with the development of the hearing process, about two weeks after birth in rats -- hair cells retain ATP receptors and these may be further exposed to the molecule whenever the release happens after exposure to loud sound, which could explain peripheral tinnitus, the authors suggested.
"If ATP were released by the remaining support cells, it may cause the sensation of sound when there is none," he said.
Supporting cells in the organ of Corti, the cochlea that is geared up with auditory sensory hair cells, is responsible for initiating electrical activity in the auditory nerve before the development of hearing, found Dwight E. Bergles, Ph.D., of Johns Hopkins, and colleagues.
According to the studies, it has been suggested that in the developing brain of animals, also if we talk about human beings, the fact is that nonsensory support cells have a vital role to play in the development of central auditory pathways.
This whole research can further explian the development of peripheral tinnitus later in life, the authors wrote in the Nov. 1 issue of Nature.
"It's long been thought that nerve cells that connect auditory organs to the brain need to experience sound or other nerve activity to find their way to the part of the brain responsible for processing sound," Dr. Bergles said. "So when we saw that these supporting cells could generate their
"It is as if ATP substitutes for sound when the ear is still immature and physically incapable of detecting sound," said Dr. Bergles. "The cells we have been studying seem to be warming up the machinery that will later be used to transmit sound signals to the brain...We think that only a few cells release ATP at one time, and that a small amount of free-floating ATP then activates only a few nearby hair cells."
The ATP-mediated signaling appears to orchestrate the output that is provided by the neighboring inner hair cells. The fact is that this whole process may provide a big amount of contribution to the mapping of the spatial location of sound perception, reception, or transmission, the authors suggested.
Although the spontaneous release of ATP by the cells stops with the development of the hearing process, about two weeks after birth in rats -- hair cells retain ATP receptors and these may be further exposed to the molecule whenever the release happens after exposure to loud sound, which could explain peripheral tinnitus, the authors suggested.
"If ATP were released by the remaining support cells, it may cause the sensation of sound when there is none," he said.