Subject: Re: A question on B=?ISO-8859-1?Q?=E9k=E9sy.?= From: David Mountain <dcm@xxxxxxxx> Date: Fri, 19 Mar 2010 16:07:01 -0400 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--0015173fe484fa123d04822ce344 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable If your real interest is the basilar membrane stiffness gradient, then I would take Fig. 11-73 on face value. I doubt very much that the "gelatinous mass" is the tectorial membrane since, as you say, von Bekesy was very familiar with the TM and results fro= m TM measurements are mentioned elsewhere in the book. The basilar membrane stiffness measurements that we measured in the gerbil are quite similar in slope to what von Bekesy found and we have some preliminary data for the dolphin basilar membrane that exhibit a similar slope. On Fri, Mar 19, 2010 at 1:58 PM, reinifrosch@xxxxxxxx < reinifrosch@xxxxxxxx> wrote: > Thank you, Harriet and David -- but I have two different answers now ! > > Harriet: could you please give details on why you think that the > "gelatinous > mass" is the TM? As you know, that verdict is hard to swallow; von Bekesy > knew the TM well. > > David: fairly ingenious! Agar and gelatin are even mentioned twice on tha= t > page 475. The helicotrema was closed with such a mixture, and after > conclusion of the measurements at the apex, the scala tympani was > closed again with agar and gelatin. With "cochlear lumen", Bekesy means > "cochlear channel", I believe. But I do not understand that page 475 > completely. Can that gelatin get into the cochlear duct ? > > It would be nice if we could now clear up this gelatinous problem. > I asked the List about it a few years ago already, I believe, but > did not get answers then. > > The problem is important to me in connection with Bekesy's > Fig. 11-73 (BM stiffness). > > Reinhart. > > ----Urspr=FCngliche Nachricht---- > Von: dcm@xxxxxxxx > Datum: 19.03.2010 17:00 > An: <reinifrosch@xxxxxxxx> > Kopie: <AUDITORY@xxxxxxxx> > Betreff: Re: A question on B=E9k=E9sy. > > The viscosity of endolymph is similar to water. The "gelatinous mass" is > probably the agar/gelatin mixture mention earlier on the same page. > > On Fri, Mar 19, 2010 at 9:20 AM, reinifrosch@xxxxxxxx < > reinifrosch@xxxxxxxx> wrote: > > > Dear colleagues, > > > > At the bottom of page 475 of his book "Experiments in Hearing", > > McGraw-Hill, New York, von B=E9k=E9sy (1960) has written: > > > > "[...] It was further established that the gelatinous mass in the > > cochlear duct increased the rigidity of the partition, especially > > near the helicotrema. [...]" > > > > What is that "gelatinous mass"? I seem to remember that > > the viscosity of endolymph is about equal to that of water. > > > > A wild guess: "gelatinous mass" =3D tectorial membrane (??) > > > > Your (on- or off-line) suggestions would be very welcome, > > of course, even if you are not absolutely sure ! > > > > 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 . > > --=20 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/hrc/research/laboratories/auditory-biophysics/ Phone: (617) 353-4343 FAX: (617) 353-6766 Office: ERB 413 --0015173fe484fa123d04822ce344 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable If your real interest is the basilar membrane stiffness gradient, then I wo= uld take Fig. 11-73 on face value.=A0 <br><br>I doubt very much that the &q= uot;gelatinous mass" is the tectorial membrane since, as you say, von = Bekesy was very familiar with the TM and results from TM measurements are m= entioned elsewhere in the book.=A0 <br> <br>The basilar membrane stiffness measurements that we measured in the ger= bil are quite similar in slope to what von Bekesy found and we have some pr= eliminary data for the dolphin basilar membrane that exhibit a similar slop= e.<br> <br><div class=3D"gmail_quote">On Fri, Mar 19, 2010 at 1:58 PM, <a href=3D"= mailto:reinifrosch@xxxxxxxx">reinifrosch@xxxxxxxx</a> <span dir=3D"ltr"= ><<a href=3D"mailto:reinifrosch@xxxxxxxx">reinifrosch@xxxxxxxx</a>&g= t;</span> wrote:<br> <blockquote class=3D"gmail_quote" style=3D"border-left: 1px solid rgb(204, = 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Thank you, Harrie= t and David -- but I have two different answers now !<br> <br> Harriet: could you please give details on why you think that the "gela= tinous<br> mass" is the TM? As you know, that verdict is hard to swallow; von Bek= esy<br> knew the TM well.<br> <br> David: fairly ingenious! Agar and gelatin are even mentioned twice on that<= br> page 475. The helicotrema was closed with such a mixture, and after<br> conclusion of the measurements at the apex, the scala tympani was<br> closed again with agar and gelatin. With "cochlear lumen", Bekesy= means<br> "cochlear channel", I believe. But I do not understand that page = 475<br> completely. Can that gelatin get into the cochlear duct ?<br> <br> It would be nice if we could now clear up this gelatinous problem.<br> I asked the List about it a few years ago already, I believe, but<br> did not get answers then.<br> <br> The problem is important to me in connection with Bekesy's<br> Fig. 11-73 (BM stiffness).<br> <br> Reinhart.<br> <br> ----Urspr=FCngliche Nachricht----<br> Von: <a href=3D"mailto:dcm@xxxxxxxx">dcm@xxxxxxxx</a><br> Datum: 19.03.2010 17:00<br> An: <<a href=3D"mailto:reinifrosch@xxxxxxxx">reinifrosch@xxxxxxxx</a= >><br> Kopie: <<a href=3D"mailto:AUDITORY@xxxxxxxx">AUDITORY@xxxxxxxx= l.ca</a>><br> Betreff: Re: A question on B=E9k=E9sy.<br> <div><div></div><div class=3D"h5"><br> The viscosity of endolymph is similar to water. =A0The "gelatinous mas= s" is<br> probably the agar/gelatin mixture mention earlier on the same page.<br> <br> On Fri, Mar 19, 2010 at 9:20 AM, <a href=3D"mailto:reinifrosch@xxxxxxxx">= reinifrosch@xxxxxxxx</a> <<br> <a href=3D"mailto:reinifrosch@xxxxxxxx">reinifrosch@xxxxxxxx</a>> wr= ote:<br> <br> > Dear colleagues,<br> ><br> > At the bottom of page 475 of his book "Experiments in Hearing&quo= t;,<br> > McGraw-Hill, New York, von B=E9k=E9sy (1960) has written:<br> ><br> > "[...] It was further established that the gelatinous mass in the= <br> > cochlear duct increased the rigidity of the partition, especially<br> > near the helicotrema. [...]"<br> ><br> > What is that "gelatinous mass"? I seem to remember that<br> > the viscosity of endolymph is about equal to that of water.<br> ><br> > A wild guess: "gelatinous mass" =3D tectorial membrane (??)<= br> ><br> > Your (on- or off-line) suggestions would be very welcome,<br> > of course, even if you are not absolutely sure !<br> ><br> > Reinhart.<br> ><br> > Reinhart Frosch,<br> > Dr. phil. nat.,<br> > r. PSI and ETH Zurich,<br> > Sommerhaldenstr. 5B,<br> > CH-5200 Brugg.<br> > Phone: 0041 56 441 77 72.<br> > Mobile: 0041 79 754 30 32.<br> > E-mail: <a href=3D"mailto:reinifrosch@xxxxxxxx">reinifrosch@xxxxxxxx= ch</a> .<br> <br> </div></div></blockquote></div><br><br clear=3D"all"><br>-- <br><br>David C= . Mountain, Ph.D.<br>Professor of Biomedical Engineering<br><br>Boston Univ= ersity<br>44 Cummington St.<br>Boston, MA 02215<br><br>Email: =A0 <a href= =3D"mailto:dcm@xxxxxxxx">dcm@xxxxxxxx</a><br> Website: <a href=3D"http://www.bu.edu/hrc/research/laboratories/auditory-bi= ophysics/">http://www.bu.edu/hrc/research/laboratories/auditory-biophysics/= </a><br>Phone: =A0 (617) 353-4343<br>FAX: =A0 =A0 (617) 353-6766<br>Office:= =A0ERB 413<br> <br> --0015173fe484fa123d04822ce344--