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What determines the frequency range we can hear?

Kalman Rubinson kr4 at nyu.edu
Mon Apr 2 03:40:46 EST 2001

On 30 Mar 2001 08:21:58 +0100, turboflier at hotmail.com ("rico r")

>How come bats can hear up to 130 kHz while we can hear up to 20 kHz? 
>Obviously we dont NEED to hear a such a high frequency, but what determines 
>the frequencies we can hear? Does it have anything to do with the size and 
>structure of the cochlea (or the sensory hairs)?

Probably but you'll need to find a good comparative anatomy source for

> Also, do specific nerves 
>respond for specific frequencies, or do the impulses just get faster? I 
>would imagine that individual nerves fire for a specific frequency, and how 
>fast they fire determines the volume of the sound.  

The firing limit for vertebrate nerve is under 1KHz.  For low
frequencies, one can get an action potential per cycle.  At higher
frequencies, multiple fibers, as an ensemble, signal frequency.
(Volley principle)

This is in addition to the specificity of individual hair cells and
nerve fibers for particular frequencies.  (Place principle)


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