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Re: from fish to CB
Thank you for adding arguments against the old idea of a mechanical
traveling wave that transmits energy from the base to the apex of
cochlea, defended by Richard Lyon.
Quoting Martin Braun <nombraun@xxxxxxxxx>:
What the hearing antennae of insects do in the air, is what the cilia of
vertebrate hair cells do in the endolymph. Some insects even produce
otoacoustic emissions with their antennae. Apparently for exactly the same
reason as vertebrates do, including humans.
Some years ago, cochlear researchers became aware of these amazing parallels
between insect and vertebrate hearing. And since 2002 they have been
inviting prominent insect researchers to their meetings.
When I mentioned Geoffrey Manley, I intended to remind this stuff.
However, mammal hearing is superior. The hair cells exhibit a highly
ordered structure with typically three rows of V-shaped bundles of
OHCs and tip links at the cilia and other peculiarities. Andrew Bell
was perhaps correct when he stressed the role of radial rather than
base-to-apex mechanics. Did he not also claim that the hair cells are
pressure sensors? Anyway, cochlear function seems to work quite
different from what was and is still belived for the transmission line
and belonging traveling wave mechanics. You certainly can add a lot of
recent results. I only recall a paper where mice with a genetic defect
had a partially irregular pattern of haircell bundles but their
hearing was not seriously affected. Maybe, such conclusions can be
misleading because the auditory system is capable of compensating
malfunctions to some extent. Should we expect models of cochlea to
mimic this excellence too?
I strongly object to Richard Lyon. Maybe, he was mislead when I argued
that the purely mathematical cosine spectrogram is similar to the
result from filter banks. This is only correct with respect to the
simultaneous, i.e., parallel input instead of serially connected
two-ports of a transmission line. While the number of IHCs is limited
to about 30 000, and there several auditory nerve fibers projecting to
each of them, the cosine spectrogram effectively works continuously
with respect to frequency since the sinc-response to an elementary
step can be calculated as accurately as necessary.
What about the CB, you will perhaps still adhere to the idea that the
brain rather than already the cochlea is reponsible for it. Is there
any news from T. Ren? His result was certainly not what Zwislocki and
the asymmetrical modelers indended to find out.
Neuroscience of Music
S-671 95 Klässbol
web site: http://w1.570.telia.com/~u57011259/index.htm
----- Original Message ----- From: "Steve Beet" <steve.beet@xxxxxxxx>
Sent: Sunday, October 07, 2007 11:13 PM
Subject: Re: diaphragm output & phase: HC selectivity ... and the lateral
organ of the fish
Ok, I really will keep it short this time!
I may be guilty of over-simplification, but to find more definitive
information about different types of microphone, click, read, and inwardly
digest everything at this URL: