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Re: Cochlea Amplifier models : a new list
Your statement "OHC's actively feed energy into the travelling wave" is
this the point you are trying to make ???
To re-address two of the papers which I consider significant ...
Robles  Figure 14 - Phase increases away from stapes ... agreed. I
have no problem with Bekesey's PASSIVE travelling wave... it is a good
thing he won a Nobel peace prize for it ... in my opinion. To us he is
like Newton. Would you agree ? A g-dfather of Auditory physics.
Ren  Figure 2 - BM motion and emissions have roughly the same phase
and same delay. The activity in the cochlea - with respect to DPOAEs and
other OAEs - are as fast (or slightly faster depending on tonotopic
location) as the travelling wave. Indeed it is now emerging that apical
emissions are quite likely FASTER ! ... further ... I believe that Ren
questions whether energy is 'fed into' the travelling wave...
particularly in his later paper these points become more clear .
By the way - on a lighter note - I would like to re-iterate someone
else's musings ... where is the Ren.T. ? Dan, is the land lord unhappy or
can we give more time for the Ren.T. ? Normally his delay is as fast as
Mechanics of the Mammalian Cochlea
L Robles, MA Ruggero - Physiological Reviews, 2001 - Am Physiological Soc
Reverse propagation of sound in the gerbil cochlea
T Ren - Nature Neuroscience, 2004 - nature.com
Group Delay of Acoustic Emissions in the Ear
T Ren, W He, M Scott, AL Nuttall - Journal of Neurophysiology, 2006 - Am Physiological Soc
On Thu, Oct 18, 2007 at 07:55:54PM +0000, reinifrosch@xxxxxxxxxx wrote:
> Hello Matt Flax and List,
> Answers to your posting of Oct. 18:
> 1) Fig. 14 of Robles and Ruggero (2001) shows data of
> Russell and Nilsen (1997), "The location of the cochlear
> amplifier: spatial representation of a single tone on the
> guinea pig basilar membrane", Proc Natl Acad Sci USA 94:
> 2660-2664; (this PNAS paper can be downloaded freely).
> Yes, animal was alive and sedated. BM displacements were
> measured using "the self-mixing effect of a laser diode".
> Light directly reflected from the BM. Fig. 1 of that PNAS
> paper is similar to Fig. 14 of Robles and Ruggero (2001),
> so you can look at the broad passive response peaks at
> x_a = 15.85 mm and at the narrower active peaks at
> x_a = 14.47 mm yourself. The phase measurements are
> shown in Fig. 2B of the PNAS paper; the phase decreases
> if x_b increases (where x_b = 19mm - x_a); this shows
> that the wave travels from base to apex.
> 2) Fig. 1C of Ren et al. (2003), "Measurement of Basilar-
> Membrane Vibration ...":
> The mentioned book "Biophysics of the Cochlea" (2003) is
> the proceedings of the international "Mechanics of Hearing"
> symposium at Titisee (Germany), July 27 to August 1, 2002.
> That book is certainly in many libraries. The mentioned
> Fig. 1C of Ren et al. demonstrates the travelling wave in
> the active-peak x_b-region especially clearly --- but the
> fact that this travelling wave exists is proven already by the
> PNAS paper mentioned under point 1 above (and by many
> other papers with phase measurements of course). I do not
> understand the part of your message from "Normally Ren's
> papers ..." to "... common knowledge". In my opinion the
> travelling wave is entirely passive from the stapes to the
> small-x_b limit of the active-peak region. Only for x_b-values
> between that limit and the top of the active peak do the
> OHC's actively feed energy into the travelling wave, as
> indicated, e.g., by the negative real part of the BM
> impedance in Fig. 3 of de Boer and Nutall (1999), discussed
> under my point 4. Would you please give me references for
> "Ren's other papers"?
> 3) Fig. 1b of Mammano and Ashmore (1993), "Reverse
> transduction ...":
> RL (Hensen-cell resonator) has a resonance frequency
> deeper, by a factor of about (1 / 2.3), than the resonance
> frequency of the BM-resonator at the same place:
> Here we appear to agree then.
> 4) Fig. 3 of de Boer and Nuttall (1999), "The inverse
> problem solved ...":
> Section VII of that paper is entitled "Conclusions and
> reasons for caution", and the first mentioned reason for
> caution is: "Long-wave behavior is assumed at and near
> (x=0)". Indeed, my calculations have yielded that for the
> considered case (guinea pigs, 16.8 kHz) the long-wave
> condition (k*H << 1; see, e.g., Section 4 of de Boer's
> chapter in the book "The Cochlea", Springer, 1996) is
> strongly violated. Possibly there are reasons to hope that
> the results of de Boer and Nuttall are approximately correct
> in spite of that violation.
> Reinhart Frosch.
> 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@xxxxxxxxxx .
> ----Ursprüngliche Nachricht----
> Von: flatmax@xxxxxxxx
> Datum: 18.10.2007 05:53
> An: <reinifrosch@xxxxxxxxxx>, <AUDITORY@xxxxxxxxxxxxxxx>
> Betreff: Re: Cochlea Amplifier models : a new list
> Dear Reinhart and list,
> In a manner similar to Martin, Richard and others, I will go
> through the examples you have pointed out.
> I also am unsure of what these points are leading to.
> I am very interested to hear your conclusion.
> Results pointed out by Reinhart:
> 1) I can confirm that you are pointing out two peaks. I am
> not sure about the particulars of the experiment - how
> visualisation was accomplished. I assume that the animal
> was alive and sedated. The locations pointed out using your
> assumptions are that :
> a] Active peak in an apical location to the passive peak
> b] Passive peak in basal location to active peak.
> 2) I can not get this reference currently. Normally Ren's
> papers are about delay. Ren's other papers have continuity
> in that they point out delays are normally as fast or faster
> then the travelling wave delay for OAEs. For this reason,
> Ren points out that active processes are too quick to
> maintain the active travelling wave hypothesis. We
> have known this point since the eighties and it should now
> be common knowledge.
> 3) I can confirm that in the dead animal, the RL responds in
> a resonant manner below the BM frequency at the same
> point of reference. The interpretation is that the RL is tuned
> more then an octave below the BM at the same tonotopic
> 4) I can see the projected negative damping which is
> calculated using inverse techniques. I trust your
> interpretation of this image which is "the distance between
> active and passive peaks is 1.4 mm and so corresponds to
> half an octave." I would like to point out that inverse
> solutions are numerical interpretations. Guiding numerical
> points of view if you will. You further reference high level
> perception of pitch "a perceived-pitch difference much
> smaller that half an octave"
> I trust that I have not mislead the readers and am repeating
> your train of thought as confirmation for the list.
> On Wed, Oct 17, 2007 at 03:11:20PM +0000, reinifrosch@xxxxxxxxxx
> > Hello Matt and List,
> > Because of a nice one-week stay in Montreal (CAA-2007
> > this reaction to your posting of Oct. 9 is very late. After
> > read the many answers to your cochlear-amplifier question,
> however, I
> > would like to suggest to some of the contributors to look at
> > following figures in journals and books. Some of my remarks on
> > four figures are very tentative of course.
> > 1) L. Robles and M. A. Ruggero (2001), "Mechanics of the
> > Cochlea", Physiological Review 81, 1306-1352; the upper part of
> > 14 shows data of Russell and Nilsen on guinea-pig BM
> > versus cochlear longitudinal position x_a in response to 15-kHz
> > sinusoidal tones; x_a, the distance from the apex, ranges from
> > to 17 mm; BM length is about 19 mm; so x_b, the distance from
> > base, ranges from about 2 to 5.5 mm. At sound pressure levels
> > of 15, 20, 25, ... , 60, 70 dB there is an active peak at about
> x_a =
> > 14.47 mm. At SPL = 55, 60, ... , 90, 100 dB there is a passive
> > at about x_a = 15.86 mm. At SPL < 55 dB no data are shown in
> > passive-peak x_a-region.
> > 2) T. Y. Ren et al. (2003), "Measurement of Basilar-Membrane
> > Vibration Using a Scanning Laser Interferometer", in the book
> > "Biophysics of the Cochlea", A. W. Gummer, ed., World Scientific,
> > Jersey, etc., 211-219; Fig. 1C shows gerbil BM velocity versus
> > distance x_b from the base in response to a sinusoidal tone of 16
> > and 40 dB (SPL). There are four curves, measured at times T/8,
> > 3T/8, and T/2, where T = (1second) / 16000 is the wave period;
> > ranges from 2.1 to 3 mm; a hint of the passive peak is visible at
> > = 2.1 mm; the active peak is at x_b = 2.6 mm and has a full width
> > half maximum of 0.25 mm. The four curves in Fig. 1C show that
> > is a wave travelling on the BM, in the +x_b-direction (i.e.,
> > base to apex), across the active-peak x_b-region. At the active-
> > centre (x_b = 2.6 mm) the phase velocity of the travelling wave
> > g., the speed of a wave zero) is 3.2 m/s.
> > 3) F. Mammano and J. F. Ashmore (1993), "Reverse transduction
> > measured in the isolated cochlea by laser Michelson
> > Nature, 838-841. Fig. 1b shows the motion of aluminium-coated
> > beads placed on the BM and on the Hensen-cell region of the RL
> > (reticular lamina) of post-mortem guinea-pigs in response to 4-
> > millisecond-long rectangular electric-current pulses. Of
> > here are the damped oscillations at the beginning and at the end
> > these current pulses, since they allow the determination of the
> > resonance frequency (i.e., the frequency that the oscillations
> > have without damping) of the resonators to which the observed
> > belong. At the observed place, the resonance frequency of the
> > resonator (spring = BM fibres; mass = organ of Corti) was found
> to be
> > 2.3 kHz, and that of the "Hensen-cell" resonator (spring = outer
> > cells and maybe elastic parts of the the Deiters cells; mass =
> > cells and other nearby structures) was 1.0 kHz. I suspect that
> > Hensen-cell resonator (oscillating so that the angle formed by
> the RL
> > and the BM varies) is the "second degree of freedom", rather than
> > tectorial membrane (TM) suspended on two springs mentioned, e.g.,
> > Section 7.1 of E. de Boer's chapter in the book "The Cochlea"
> > (Springer, 1996).
> > 4) E. de Boer and A. L. Nuttall (1999), "The 'inverse problem'
> > solved for a three-dimensional model of the cochlea. III.
> > the solution method.", JASA 105, 3410-3420; the lower panel of
> Fig. 3
> > shows the guinea-pig BM impedance (across-BM pressure
> > divided by BM velocity) versus location x_b (expressed in percent
> > 6 mm) for a sine-tone of 16.8 kHz and 20 dB (SPL). In the region
> > 67 to 84 percent, i.e., from x_b = 4.0 to x_b = 5.0 mm, the real
> > of the impedance is negative; that implies "negative damping"; i.
> > it implies that in this x_b-region the outer hair cells (OHC's)
> > energy into the travelling wave. At locations x_b < 4.0 mm, the
> > resonance-peak frequency region of the Hensen-cell resonator
> > point 3 above) is above 16.8 kHz so that these resonators are
> > excited significantly by the wave. At x_b = 4.0 mm, the low-
> > limit of the just mentioned resonance-peak frequency region is
> > 16.8 kHz, so that from that location onwards the resonator is
> > excited, and the motor proteins in the OHC walls are caused to
> > operate, maybe both via modulation of the electric current into
> > OHC hairs and via direct mechanical stimulation of the OHC walls.
> > x_b > 5.0 mm, the Hensen-cell-resonator's resonance-peak region
> > below 16.8 kHz, so that the OHC's do not feed energy into the
> > travelling wave. The highest point of the active peak, shown in
> > upper panel of Fig. 3, (i.e., the characteristic place of the
> > kHz-20-dB wave) is at that last-mentioned position of x_b = 5.0
> > Extrapolation of the short-dashed curve in the lower panel
> > that the imaginary part of the BM-impedance vanishes at about x_b
> > 130 percent = 7.8 mm; thus the resonance frequency of the BM-
> > oscillator (see point 3 above) at x_b = 7.8 mm is 16.8 kHz. The
> > kHz travelling wave does not reach that point. According to the
> > panel, the passive peak (same wave, dead OHC's) is at about x_b =
> > percent = 3.6 mm. Thus the distance between active and passive
> > is 1.4 mm and so corresponds to half an octave. In the case of
> > similar, but lower-frequency waves in human ears, e.g. 1kHz,20dB
> > 1kHz,100dB, there is a similar x_b-difference but (since mostly
> > information is used) a perceived-pitch difference much smaller
> > half an octave; see, e.g., Chapter 6 of "An Introduction to the
> > Psychology of hearing" by B. C. J. Moore, Academic Press,
> > etc., 5th ed., 2003.
> > Reinhart Frosch.
> > 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@xxxxxxxxxx .
> > ----Ursprüngliche Nachricht----
> > Von: flatmax@xxxxxxxx
> > Datum: 09.10.2007 11:35
> > An: <AUDITORY@xxxxxxxxxxxxxxx>
> > Betreff: Cochlea Amplifier models : a new list
> > Hello,
> > After our discussion last week, I have made a new list of
> > physiological Cochlea Amplifiers (some of these are weakly
> > physiologically based). [...]
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