Subject: Re: BM motion From: "D. Sen" <dsen@xxxxxxxx> Date: Wed, 14 Nov 2007 11:35:58 -0500 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Yes, it is also possible to model the effect (low and high side 2TS) using passive models. David Mountain wrote: > Conventional traveling-wave theory does account for high-side suppression. > In an active cochlea, as the traveling wave approaches its best location, > it is amplified over a region basal to the peak. If the suppression tone > excites this basal region, it will interfere with the amplification > process. > > For more information on the spatial extent of high-side suppression, see: > > Javel E, Geisler CD, Ravindran A. > Two-tone suppression in auditory nerve of the cat: rate-intensity and > temporal analyses J Acoust Soc Am. 1978 Apr;63(4):1093-104. > > -------------------------------------------------------------------- > > David C. Mountain, Ph.D. > Professor of Biomedical Engineering > > Boston University > 44 Cummington St. > Boston, MA 02215 > > Email: dcm@xxxxxxxx > Website: http://www.bu.edu/dbin/bme/faculty/?prof=dcm > Phone: (617) 353-4343 > FAX: (617) 353-6766 > Office: ERB 413 > On Wed, 14 Nov 2007, Matt Flax wrote: > >> 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' >> > >