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Re: candidates for the cochlear amplifier
At the first glimpse I misunderstood the word list and thought why not
using Jont's list for the nittygritty?
I feel a bit guilty. A while ago Lionel Naftalin and Azzo Azzi sent to
me their papers because they were not taken seriously elsewhere.
Perhaps, they are wrong.
I am unable to judge which suggested mechanism fits best.
Being an electrical engineer, I wonder if the role of electrical
phenomena is already clarified sufficiently. Azzi points to the
Is there anybody to whom I could redirect my Azzi papers?
Is there new work by Fettiplace?
The CRC-book 'Active Filters, Theory and Design' by Pactitis will
perhaps not answer all our questions.
I object to the attitude by Reinhard Frosch, Richard Lyon and others
in so far as the word traveling wave should not be misused just
because there is a common desire to defend an established erroneous
After our discussion last week, I have made a new list of possible
physiological Cochlea Amplifiers (some of these are weakly
physiologically based). I currently count seven.
Can anyone think of other physiologically based CAs to add to the list ?
If so then please add them and change the subject line.
a] Oscillators : Van Der Pol type oscillators, which I believe began
with Johannesma 
Explains high amplification.
Weakness: No particular physical mechanism, does not explain propagation.
b] Squirting wave : Andrew Bell's Organ of Corti squirting amplifier 
Technically inspired. Advantage: Focus on radial direction.
Role of some mechanical resonance parameters neglected.
c] Dual resonance : Martin Braun's dual resonance model 
If mechanics of BM would only protect hair cells, then one could not
understand why mammals reach much higher frequencies.
d] Feedback amp. : Zwicker's feedback amplifier 
No specified physiolgical mechanism.
e] Hopf amplifier : Hopf bifurcation augmenting the travelling wave [5,6]
PRL prints any defense of TW.
f] Active TW : Active travelling wave amplifiers - of which I
believe there are many, I reference only one 
Tautology in combination with defense of an obviously wrong concept.
I would agree if we clarify that a bank of cochlear amplifiers
amplifies the local mechanical mainly up and down as well as radial
back and forth directed motion in a manner that looks like a wave that
g] Active CW : Active compression wave amplifier. Of which I have
seen no complete models - as of yet.
Cochlear activity indeed causes measurable OAEs, which are, however,
most likely not yet the whole story. Compression waves would not act
like tuned filters.
In all: Neither of the candidates is already my only favorite.
As long as there is no more detailed understanding, we have to ask
what practical application a model might have. Models that predict
reflected waves are presumably not appropriate. Non-linearity resides
in the unidirectionality of hair cells.
While at the time of Lighthill, unapt mechanical models were overly
tweaked in order to by force fit psychoacoustic measurements, I
recommend to conclude from directly measured data to what extent
phenomena like tuning curve can be ascribed just to basilar membrane.