Cochlea -- quality of filtering

Jeffrey Sirianni sirianni at uts.cc.utexas.edu
Thu Sep 21 22:41:09 EST 1995


In article <43oll3$gt2 at hollywood.cinenet.net>, erc at cinenet.net (Eric Smith) says:
>
>
>How well does the cochlea divide sound into its frequency components?
>For example, a 100 dB, 6000 Hz, pure tone, stimulates the hair cells
>for 6000 Hz.  But does it avoid stimulating any 5000 Hz hair cells at
>all, or does it stimulate those with a small fraction of the energy it
>applies to the 6000 Hz hair cells?  Can anyone supply any kind of
>formula for estimating how much stimulation there will be at different
>frequencies when a single pure tone is applied?
>

Our mind has the ability to hear such a loud tone as simply a tone, but when
a sound of this magnitude is presented to the cochlea, many auditory
nerve fibers on both sides of the tonal frequency are activated.  So why
do we not perceive this as a complex sound?  The brain's 2nd and 3rd order
neurons suppress the activity on the sidebands.  This is an oversimplied
answer to this question, but I would suggest reading Kim and Molnar (1979)
J. Neurophysiol. 42:16-30.  I think this is the right article... Help from
others appreciated...

Jeff Sirianni     @(((<{
University of Texas at Austin
Communication Sciences and Disorders
CMA, 2nd Floor Clinic
Austin, TX  78712-1089
sirianni at uts.cc.utexas.edu
jgsaudio at aol.com



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