Re: BM motion (Matt Flax )


Subject: Re: BM motion
From:    Matt Flax  <flatmax@xxxxxxxx>
Date:    Wed, 14 Nov 2007 16:08:12 +1100
List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>

Hi list and Richard, Travelling waves have no mechanism for high side suppression... it is simply not possible. Clearly in the literature [1] last paragraph for example ... here is an excerpt : ... neither models nor experiments have yet answered what is perhaps the central question of mammalian cochlear physiology, namely, the origin of the CF specificity of two-tone suppression and other mechanical nonlinearities. I have other references. [1] @xxxxxxxx{Ruggero:1992, author = {Ruggero, M.A. and Robles, L. and Rich, N.C.}, title = {Two-tone suppression in the basilar membrane of the cochlea: mechanical basis of auditory-nerve rate suppression}, journal = {Journal of Neurophysiology}, year = {1992}, volume = {68}, pages = {1087-1099}, number = {4}, month = {October} } On Tue, Nov 13, 2007 at 08:22:06PM -0800, Richard F. Lyon wrote: > No matter how the nonlinearity affects the tone amplitudes, the sum of two > sinusoids of different frequencies is easily distinguishable from a larger > single sinusoid, through the temporal pattern, which will be appararent in > the auditory nerve firing-time patterns, even when both frequencies are > higher than can be coded by synchrony. > > As to the nonlinearity, it shows up clearly in the mechanics, when the OHCs > are functioning, and it's not hard to see how OHCs in one region can change > the response to other tones that travel through that region to be localized > further on; that is, how high-f can suppress low-f if not too much lower. > The other direction works slightly differently, but the key is that > different frequencies share the same traveling wave medium that amplifies > them, so you get suppression. There may yet be mysteries in the > micromechanical details, but not in the overall functional effect. > > Matt, is the "'frequency specificity' mystery" something that you find in > the literature? Or do you just mean you haven't found a clear enough > explanation? > > Dick -- ,dPYb,,dPYb, I8 IP'`YbIP'`Yb I8 http://www.flatmaxstudios.com/ I8 8II8 8I 88888888 http://www.flatmax.org I8 8'I8 8' I8 I8 dP I8 dP ,gggg,gg I8 ,ggg,,ggg,,ggg, ,gggg,gg ,gg, ,gg I8dP I8dP dP" "Y8I I8 ,8" "8P" "8P" "8, dP" "Y8I d8""8b,dP" I8P I8P i8' ,8I ,I8, I8 8I 8I 8I i8' ,8I dP ,88" ,d8b,_,d8b,_,d8, ,d8b,d88b,dP 8I 8I Yb,d8, ,d8b,dP ,dP"Y8, PI8"888P'"Y8P"Y8888P"`Y8P""Y8P' 8I 8I `YP"Y8888P"`Y8" dP" "Y8 I8 `8, I8 `8, I8 8I Public Projects : I8 8I http://sourceforge.net/search/?type_of_search=soft&words=mffm I8, ,8' http://www.psysound.org "Y8P'


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