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Re: auditory distortion caused by yawning



Dear Roger, Harriet, Yi-Wen, and others,

the middle ear part of the story has already been pointed out by Harriet. But this part does not explain the temporary perception of musical dissonance. This, most likely, has a neural origin.

What probably happens is this:

1) Under normal conditions extended yawning can open the Eustachian tube on one or both sides. If the tubes open on both sides, they usually do it with a time lag, due to differences in the current tube conditions between left and right.

2) Opening of a tube instantaneously eliminates any over- or under-pressure that may exist in a middle ear. After this, pressure in outer and middle ear is the same, which causes an improvement of the compliance of the tympanic membrane. As a result, more sound enters the cochlea, and what we hear suddenly appears louder.

3) An inevitable result of increased sound level in the cochlea is a realignment of upward (afferent) and downward (efferent) neural signaling between cochlea and auditory brain. The realignment of efferent signaling occurs on many levels in the brain, in several sub-machineries of the cochlear outer hair cells (the amplifying motor cells of the cochlea), and with various time lags of milliseconds, seconds, and minutes.

4) Efferent servo-steering varies along the spectral map of the cochlea. Therefore also efferent realignment varies with frequency. Thus, during a yawning triggered transition period, timbres can appear in unusual shapes, which can be perceived as dissonance.

Sure, if swimming and diving is part of the story, temporary attenuation in the ear canal, due to a collaboration of ear wax and water, must also be considered.

Martin

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Martin Braun
Neuroscience of Music
S-671 95 Klässbol
Sweden
web site: http://w1.570.telia.com/~u57011259/index.htm



----- Original Message ----- From: "Yi-Wen Liu" <jacobliu@xxxxxxxxx>
To: <AUDITORY@xxxxxxxxxxxxxxx>
Sent: Friday, October 17, 2008 8:28 PM
Subject: Re: auditory distortion caused by yawning



Dear List,

I have a similar experience when I listen to music after swimming in
an outdoor pool.  In my case, musical scale  would sound warped --
even a familiar C major chord sound dissonant momentarily.  The effect
would last for about 10 minutes.  I suppose it is not filtering or
attenuation effects due to water left in my ear canal.  Does anybody
have similar experiences or an explanation?

Have a nice weekend,
Yi-Wen

On Fri, Oct 17, 2008 at 10:56 AM, Prof Roger K Moore
<r.k.moore@xxxxxxxxxxxxxx> wrote:
Dear List,

I have often noticed that if I yawn while listening to music, I experience a
noticeable distortion of the auditory experience - in particular, the sounds
appear to become discordant. Is this a well known effect, and can it be
easily explained as the result of a physical distortion of the cochlea? If
so, what does it say about timing-based theories of timbre perception?


Best wishes

Roger K. Moore

P.S. I see that there was a short discussion on this in the LIST in 2004,
but no conclusion was reached.