Re: mechanical cochlear model (Jose Ignacio Alcantara )


Subject: Re: mechanical cochlear model
From:    Jose Ignacio Alcantara  <jia10@xxxxxxxx>
Date:    Tue, 22 Feb 2011 23:03:17 +0000
List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>

A heartfelt ditto to this! Long may they live and prosper on this list. Jose On 22 Feb 2011, at 21:59, Linda Seltzer wrote: > My vote is to keep the discussion on the list, and the postings do not > have to be short. I believe that it is laudable when people want to > provide education to others and share the benefit of their expertise. >> Hello ! >> >> I, too, would be glad if the cochlear-mechanics discussion on the Auditory >> List could continue. If possible, the postings should be kept short. >> >> Today I would like to continue my point-by-point comments >> on the posting of March 7 by Andrew Bell: >> >>> In addition to Martin's 2 pieces of evidence against the traveling wave >>> model, we can add: >>> [...] >>> 2. The variation in stiffness is inadequate to tune the cochlea from 20 >>> to >>> 20000 Hz. Three decades of frequency calls for a million times variation >>> in >>> stiffness (more than between foam rubber and tungsten), and this is in >>> contrast to measurements of 2 or 3 orders at most. See Naidu & Mountain >>> 1998, Hear Res 124, 124. Bekesy found the value to be about a >>> hundred-fold >>> (p. 476 of Exp in Hearing). >> >> The human BM resonance frequency, f_BMR = (1 / 2pi) * sqrt(S / M) at >> the base appears to be about 20 kHz. At the apex, however, that >> resonance frequency may well be considerably greater than 20 Hz. >> >> Both in post-mortem and healthy cochleae, the travelling wave does >> not reach the BM resonance place. At given frequency >1 kHz the >> passive (active) response peak is basal of the BM resonance place >> by about 1.0 (0.5) octave distance. In homo, that distance is ~5mm. >> >> Reinhart. >> >> Reinhart Frosch, >> Dr. phil. nat., >> r. PSI and ETH Zurich, >> Sommerhaldenstr. 5B, >> CH-5200 Brugg. >> Phone: 0041 56 441 77 72. >> Mobile: 0041 79 754 30 32. >> E-mail: reinifrosch@xxxxxxxx . >> Dr José Ignacio Alcántara Department of Experimental Psychology University of Cambridge Downing Street Cambridge, UK CB2 3EB Phone: 44 (0)1223 764412 Fax: 44 (0)1223 333564 Fellow of Fitzwilliam College Cambridge, UK CB3 0DG Phone: 44 (0)1223 472126


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