Re: Reverse traveling wave does not exist

[Martin Braun <nombraun@xxxxxxxxx>]

On Tuesday, March 30, 2004, David Mountain wrote:

> The design of Ren's experiment has a serious flaw.

Aaaah, .......... I see.          What I do not see, however, is a flaw.
Ren's new paper in Nature Neuroscience is an excellent one, and it will soon
be considered as a landmark in cochlear research. It will probably have a
similar impact as his 2002 paper in PNAS: first a couple of outcries, and
then - after a while - research groups around the globe discussing it and
trying to adapt their thinking.

A few years ago, members of this list complained about too specific cochlear
discussions. Now there is also the Cochlea List, and I replied to David in
more detail there:

http://mimosa1.incubator.uiuc.edu/pipermail/cochlea/2004-March/001669.html

As a more general remark, just let me add this. The notion that otoacoustic
emissions (OAEs) depended on a backward traveling wave was unrealistic from
the beginning, and it should have been given up immediately (in the early
1980s), when OAEs were recorded in animals where all inner ear traveling
waves are anatomically impossible.

It should then be added that, with a different experimental design but also
in the gerbil, Tianying Ren, Jiefu Zheng, Ning Hu, Yuan Zou, and Alfred L
Nuttall also found no evidence for a reverse traveling wave, but instead for
AOEs via a fluid compression wave (Abstract 1015 from ARO 2004):

http://mimosa1.incubator.uiuc.edu/pipermail/cochlea/2004-March/001669.html

Köppl C (1994) Otoacoustic emissions as an indicator for active cochlear
mechanics: A primitive property of vertebrate auditory organs. In: Advances
in Hearing Research, eds Manley GA, Klump GM, Köppl C, Fastl H, Oeckinghaus
H. World Scientific, Singapore, pp 207-216.

Ren T (2002) Longitudinal pattern of basilar membrane vibration in the
sensitive cochlea. Proceedings of the National Academy of Sciences, USA,
early edition, Dec 2, 2002 (pnas.262663699).

Ren T (2004) Reverse propagation of sound in the gerbil cochlea. Nature
Neuroscience, early edition, Mar 21 (doi:10.1038/nn1216).

Martin

--------------------------------
Martin Braun
Neuroscience of Music
S-671 95 Klässbol
Sweden
web site: http://w1.570.telia.com/~u57011259/index.htm