Subject: Please unsubscribe me From: Sally Haggard Bogacz <sallybogacz(at)YAHOO.COM> Date: Tue, 19 Oct 2004 09:00:09 -0700Please unsubscribe me from this list. --- Automatic digest processor <LISTSERV(at)LISTS.MCGILL.CA> wrote: > There are 5 messages totalling 278 lines in this > issue. > > Topics of the day: > > 1. Traveling waves or resonance? (5) > > ---------------------------------------------------------------------- > > Date: Mon, 18 Oct 2004 15:51:26 +1000 > From: Andrew Bell <andrew.bell(at)ANU.EDU.AU> > Subject: Re: Traveling waves or resonance? > > Martin: > > I think your efforts at clarification actually muddy > the waters, as I = > can't > agree with your attempts to dispel two "popular > misconceptions". > > 1. Of course Gold predicted spontaneous otoacoustic > emissions as well as = > the > cochlear amplifier. The reason is that the former > depend on the latter. = > As > he explained it, positive feedback could easily be > excessive and lead to > continuous oscillation. Following the logic through, > he placed a = > microphone > in an ear canal and tried to detect the oscillation. > A wonderful = > experiment > that had to wait until Kemp's efforts a quarter of a > century later for > success. > > You criticise Gold's experiment because he caused > the ear to ring = > beforehand > by imposing a loud sound, so you say he was really > trying to detect = > tonal > tinnitus. Yes, there is a leap in logic in linking > tonal tinnitus with > spontaneous mechanical activity produced by positive > feedback in the > cochlea, but the leap is reasonable - both phenomena > have similar > characteristics (continuous narrow-band oscillation) > and relate to the = > ear. > > It turns out that usually the frequencies of the two > phenomena are > different, but there are cases in which the > objective SOAE frequencies = > match > the subjective ones (as you allow with your > qualifier "vast majority of > cases"). I can subjectively hear the 1440 Hz SOAE in > my left ear, for > example. But then you say tinnitus can "never" be > picked up with a > microphone, which, in the light of the foregoing, is > clearly not the = > case. > Even if you meant that tinnitus originating as > neural activity can never > drive the cochlea in reverse and be detected with a > microphone, that is = > just > a preconceived notion, as we just don't know. It's a > leap of logic which = > is > exactly the opposite of Gold's conjecture that > tinnitus _always_ has a > counterpart in the cochlea and ear canal. > > I remain open-minded on the possible connection > between the subjective > (tinnitus) and objective (SOAEs) aspects of the > auditory system. It's an > exciting one that is best not prejudged. As the > saying goes, if it looks > like a duck, sounds like a duck, and walks like a > duck, then it's very > likely that it is a duck. > > 2. I would not dismiss as "silly" Gold's argument > that amplification = > before > detection is a sound strategy in signal detection. > It means that > signal-to-noise ratio is preserved, and that is a > fundamental physical > principle which has to be obeyed in order to detect > signals down at the > theoretical limits.=20 > > > Andrew. > > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Andrew Bell > Research School of Biological Sciences > The Australian National University > Canberra, ACT 0200, Australia > T: +61 2 6125 9634 > F: +61 2 6125 3808 > andrew.bell(at)anu.edu.au > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > -----Original Message----- > From: AUDITORY Research in Auditory Perception > [mailto:AUDITORY(at)LISTS.MCGILL.CA] On Behalf Of > Martin Braun > Sent: Monday, 18 October 2004 4:42 AM > To: AUDITORY(at)LISTS.MCGILL.CA > Subject: Re: [AUDITORY] Traveling waves or > resonance? > > On Friday, October 15, Andrew Bell wrote: > > > .... Happily, > > progress has been made in my endeavours to revive > a resonance theory = > of > > hearing > > Current knowledge on resonance, traveling waves, and > amplifiers in the = > inner > ear goes well beyond that what Andrew Bell now > reviews. Also, the main = > parts > of this information is easily accessible on the web. > > I would like to comment, however, on two popular > misconceptions, which = > were > now repeated again, and for which no, or very > little, information is > available on the web. > > 1) Thomas Gold predicted the cochlear amplifier, but > not otoacoustic > emissions (OAEs). The "ringing in the ear" which he > tried to measure, = > was > tonal tinnitus, which, in the vast majority of > cases, has nothing to do = > with > OAEs. Such tinnitus is nearly always neurally based > and can never be = > picked > up with any microphone. > > 2) Gold's argument that the inner ear "needed" a > mechanical amplifier = > before > the stage of neural transmission is actually quite > silly. Other sensory > organs have their amplification cascades on a > biochemical level within = > the > sensory cells. The same also works in hearing. Only > birds and mammals = > have > specialized mechanical pre-amp cells, as an > additional mechanism. This > "design" provides several advantages, but it is by > no means a = > precondition > of hyper-sensitive hearing. > > Martin > > ---------------------------- > Martin Braun > Neuroscience of Music > S-671 95 Kl=E4ssbol > Sweden > web site: > http://w1.570.telia.com/~u57011259/index.htm > > ------------------------------ > > Date: Mon, 18 Oct 2004 15:01:24 +0200 > From: Eckard Blumschein > <Eckard.Blumschein(at)E-TECHNIK.UNI-MAGDEBURG.DE> > Subject: Re: Traveling waves or resonance? > > Dear Martin, > > May I ask you and Martin for not neglecting our > common === message truncated === ===== Sally Haggard Bogacz Ph. D Clarify Concepts Email: sally(at)clarifyconcepts.com www.clarifyconcepts.com