Re: Cochlea Amplifier models : a new list

[Martin Braun <nombraun@xxxxxxxxx>]

Gestur Björn Christianson wrote:

> > Caution is good, but there is also something like reasonable  treatment 
> > of data. Both you and Erik have not mentioned the fact  that the peak 
> > split at 100 dB showed up in two separate experiments  in the same animal 
> > (Figs. 7A and 7B). Further both of you have  disregarded the finding that 
> > in both experiments (Fig. 7A and 7B)  there are two (Fig. 7A) and three 
> > (Figs. 7B) lower rate level  points between the two peaks, not one. Thus 
> > it is simply not  possible to attribute the findings of these authors to 
> > stochastic  fluctuation.
>
> My point is that in the absence of variability data, it is impossible  to 
> say whether any of those points are lower than the others.  Your  claim of 
> the last sentence requires data the paper does not present.

No paper reports "variability data" of neural recordings. I am afraid that 
two members of this list do not know what they are talking about. It is just 
not useful, and usually quite impossible, to record a neuron ten times for 
each exposure condition and then calculate "variability data". Instead, what 
is done is that the firing response is averaged over a relatively long 
recording period. Experienced researches know how long the recording periods 
have to be, and nobody would even think of multiple repeats and "variability 
data". The data points in Figs. 7A-D of Geisler et al. (1974) are as clear 
and as significant as data can be.


> > Most importantly, none of your or Erik's concerns question the  finding 
> > that the first fiber neural data do NOT mirror the half- octave shift 
> > seen in basilar membrane (BM) behavior.
>
> This is an unrelated point.  Based on principles and data that no one  has 
> yet questioned (that the auditory nerve fibres are connected to  hair 
> cells which in turn are driven by a limited region of the  basilar 
> membrane),

The "principle" that the hair cells "are driven by a limited region of the 
basilar membrane" has been questioned by many researchers for many years.

Rémy Pujol and his colleagues in France state on their outstanding inner ear
website:

"The traveling wave tends now to be considered an epiphenomenon."

http://www.cochlea.org/

where you have to go to "cochlea", then "physics", then last paragraph.


The data of Figs. 7A-D and Fig. 8 of Geisler et al. (1974) are strong 
evidence in support of this view:

http://jn.physiology.org/cgi/reprint/37/6/1156?ijkey=31b75671bc6ad3014949ac04154809ec6d4ade00&keytype2=tf_ipsecsha

In fact, these data are a further piece of evidence that disproves Bekesy's 
concept of cochlear function.

Martin



----- Original Message ----- 
From: "Gestur Björn Christianson" <g.christianson@xxxxxxxxx>
To: <AUDITORY@xxxxxxxxxxxxxxx>
Sent: Friday, October 12, 2007 12:42 PM
Subject: Re: Cochlea Amplifier models : a new list