Sunday, January 18, 2009

We're suspicious of wikipedia's tinnitus piece

We posted about electronic regeneration and human hearing a while back. At the time, it sounded just a bit too good to be true. While we haven't completely disproved the idea, we did run across this snippet from, which offers no support - but is pretty amazing:

Stereocilia are stimulated by shear force from the moving endolymph. The cell creates an electrical response to sound vibrations that in turn causes the organ of Corti to sway and the stereocilia to tilt. Tilting movements of the stereocilia affects the tension on the filaments in the tip link which opens and closes the gated ion channels. When tension increases, the flow of ions across the membrane into the hair cell rises as well. Such influx of ions causes a depolarization of the cell resulting in an electrical potential that ultimately leads to a signal for the auditory nerve and the brain. The gate of the ion channel swings a distance of about 4 nm each time it opens. The filaments in-between the stereocilia are extremely sensitive and stretch about .04 nm with even the faintest sound humans can detect, which is a little under the radius of a hydrogen atom.
In this context, 30nm really is an enormous amount!

UPDATE: Well, could be...

There is a descending efferent auditory pathway that parallels the afferent pathway and is influenced by ascending fibers via multiple feedback loops. The specific function of this system in audition is not well understood, but clearly modulates central processing and regulates the input from peripheral receptors in a fashion similar to the role played by the efferent vestibular system.


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