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Re: HC selectivity ... was Re: Physiological models of cochlea activity - alternatives to the travelling wave
Yes - thanks for correcting me Bob.
Allow R to vary from 15 to 80 Meg Ohms ... as per the reference.
R= 15 Meg Ohms ... taken from  for example
C= 1 pF ... taken from  for example
This is about 10 kHz ... more accurate measurements will most likely
take this figure to higher frequencies.
Whilst this seems low - as we can hear up to 20 kHz, my initial
statement on hair cell selectivity is this :
The resistor capacitor model of the basolateral hair cell membrane is
flawed. It is flawed for these reasons - as well as others :
a] Membranes are not linear and can't be modelled by a resistor and
b] Cells have active elements ...
I predict that the affect of any 'selectivity' will be around 5% of the
total signal level through the hair cell - maximum. This is due to the
hair cell activity.
Hair cells are excellent instantaneous transducers. My upcoming thesis
will prove this... using a physiological model.
On Fri, Sep 28, 2007 at 08:24:35AM -0400, Bob Masta wrote:
> On 28 Sep 2007 at 12:55, Matt Flax wrote:
> > With respect to a hair cell at rest ... take the following general
> > values for membrane resistance and capacitance :
> > R= 40 Meg Ohms ... taken from  for example
> > C= 1 pF ... taken from  for example
> > The first order cut-off frequency would be about 25 kHz.
> > fc=25 kHz.
> How do you obtain this 25 kHz value? Using
> f = 1 / (2 * pi * R * C)
> I come up with about 4 kHz.
> Best regards,
> Bob Masta
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