Re: cochlear discussions

[Andrew Bell <bellring@xxxxxxxxxxxxxxxx>]

Dear Neil:

you wrote...

>But this raises a question. The Lighthill model is surely also agnostic as
to which particular
>physical structures in the cochlea constitute the mass/spring elements of
the travelling wave,
>since it is just a piece of mathematics, and therefore perfectly applicable
to the  tectorial
>membrane(TM)/OHC interaction. In which case is it really meaningfull,
Andrew, to make a
>distinction between the "travelling wave" theory and the "resonance"
theory? Or is it just an
>argument about what are the essential structural elements of the cochlea?

This is just the point of the recent discussion on this list in which I gave
a positive answer to Antony Locke's question of whether the traveling wave
was "an epiphenomenon". I suggested (in my post of 28/6) that, in a sense, a
graded delay in a bank of tuned resonators can be seen as a TW, making the
TW epiphenomenal -- because it doesn't carry energy. However, in Jont
Allen's post in reply (29/6), he pointed out that the TW also embodies
additional, theoretically based, hydraulic elements that couple to the
basilar membrane and carry energy from one partition element to the next. So
we have ended up with two different (incompatible) mechanisms distinguished
by how energy propagates in the cochlea, as well as by what the
frequency-analysing elements are.


Andrew.