Switching the direction of hair cells

Radium glucegen at excite.com
Fri Jul 25 05:49:53 EST 2003


Kalman Rubinson <kr4 at nyu.edu> wrote in message news:<eb7thv0mb36sfap6ja5b295jscamm8vplm at 4ax.com>...
> On 23 Jul 2003 08:39:18 +0100, glucegen at excite.com (Radium) wrote:
> 
> >No. In the norm, the higher-frequencies (moving hair cells in the
> >front of the cochlea) are perceived as higher-pitched, while
> >lower-frequencies (moving hair cells at the back of the cochlea) are
> >perceived as low-pitched.
> >
> >If this was reversed it would be interesting. Lower-frequencies would
> >be higher-pitched and higher-frequencies would be lower-pitched.
> 
> How can you possibly do this?  The direction of the pressure input is
> not the issue; it is the dynamic properties of the basilar membrane
> and the hair cells themselves.
> 
> >A cassette played at higher speed than recorded while sound abnormally
> >low-pitched. If played at a lower speed than recorded, it would sound
> >abnormally high-pitched.
> >
> >Faster vibrations would be lower-pitched and slower vibrations would
> >be higher-pitched.
> >
> >I always wonder what it would be like.
> 
> You are describing your preconceptions of a transformation that has to
> be made AFTER the hair cells.
> 
> >On my MIDI keyboard when I play a higher note for a tone instrument
> >(e.g. an accordian) I feel the vibration to be faster. When playing a
> >lower note, I feel the vibration to be slower. If the "pitch
> >receptors" in my cochleae were switched, I would feel the higher-notes
> >to vibrate slower than the lower-notes. Right?
> 
> Nah.  Just switch hands.
> 
> Kal

Actually the pitch perception has to do with the nerve endings
supplying hair cells, the location of those nerve ending, the types of
signals made by those nerve endings, and the amount of the nerve
endings stimulated in the particular area of the cochlear hairs.

Sound that stimulates hairs in the entrance of the cochlea is
perceived as higher-pitched than sound that stimulates hairs in the
back the the cochlea because that is what our brains interpret it as.

Information from nerve-endings in the front of the cochlea activate a
different portion of the auditory cortex and thus produce a different
pitch perception than information from nerve-endings in the rear of
the cochlea.

The sound itself has little to do with pitch perception. It is the
nervous system from the inner ear to the brain which is most
significant.




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