Re: The climb of absolute pitch

[Mitchell Cotter <mcotter7@xxxxxxxxx>]

Why still all this talk about the BM when it is the tectorial membrane that contacts

the array of hair cells? The hair cells are the operative producers of neural input

 to the auditory neural network of the midbrain that forms the pathway to the CNS.

Why also are cochlea curved in a characteristic spiral? The tectorial membrane 

likewise  follows this curved geometry. 

Traditional work in the field has generally neglected the work of Jim Fulton which

satisfactorily explain some compelling facts of cochlea. They are spiral curved in a 

particular manner. The launching of energy into cochlea transmits the energy to the

tectorial membrane.  The tectorial membrane surface has exactly the appropriate

dynamical properties providing for a Surface Acoustic Wave propagating along the

spiral curve which is the basic spectrometer occurring BEFORE the neural processes

operating on the signals from the numerous hair cell nerves. So hair cells  operate 

on this spiral curved surface as well. Aging of tectorial membrane's surface could 

explain a lot of aging pitch shift effects since this alters the energy launching place 

from such a curved surface acoustic wave.

Jim Fulton has published a remarkably compelling account of all the features of 

all such spiral cochlea found in animals. 

His work is easily available on the internet, which is there for anyone to peruse.  

Sadly most in the field have neglected examining it.

Mitchell Cotter

mcotter7@xxxxxxxxx

On Tue, Dec 4, 2012 at 5:38 PM, Chuck Larson <clarson@xxxxxxxxxxxxxxxx> wrote:

To all of you experts on absolute pitch, I have a question for you.

I've been following your discussion on AP musicians in hopes that I would
learn something from you that would explain some of our EEG results. We
have tested musicians with absolute pitch and relative pitch on a
vocalization experiment in which they heard their voice (through
headphones) either shift up 100 cents or down 100 cents.  The shifting was
done with a harmonizer.  We also recorded ERPs triggered by the onset of
the pitch-shift stimulus.  In general the musicians with AP had larger
magnitude left hemisphere potentials (P200) than did the relative pitch
musicians.  However, we also noted that for the UPWARD pitch-shift
stimulus, the P200 in the AP musicians, in contrast to the RP musicians,
was more strongly left lateralized than for DOWNWARD pitch shifts.  I am
trying to figure out why an upward shift in voice pitch auditory feedback
in AP musicians would show stronger left hemisphere activation than a
downward pitch shift.

I'D greatly appreciate any ideas you may have on this.

Thanks,

Chuck




________________________________________

Chuck Larson
Dept. of Communication Sciences and Disorders
Room 3-348
2240 Campus Dr.
Northwestern University
Evanston, IL 60208
Phone: 847-491-2424
Cell: 847-830-5432
Fax: 847-491-4975
email: clarson@xxxxxxxxxxxxxxxx

On 12/3/12 7:38 PM, "Kevin Austin" <kevin.austin@xxxxxxxxxxxx> wrote:

>Thanks.
>
>I had been led to believe that frequency was encoded along the BM, and
>that pitch was the interpretation of this stimulus.
>
>Kevin
>
>
>

>On 2012, Dec 2, at 8:47 AM, Bob Masta wrote:
>
>> Can someone explain the supposed mechanism behind neural timing and
>>pitch shift?   I don't understand what is being proposed.  As I
>>undestand it, since pitch is encoded as *place* along the BM, the
>>neurons respond with a firing rate that encodes *loudness* for their
>>particular frequency place.  The firing rate does not encode the
>>frequency of  the sound itself.
>>
>> What am I missing here?
>>
>> Best regards,
>>
>> Bob Masta
>>
>> =============
>> On 1 Dec 2012 at 9:50, Pierre Divenyi wrote:
>>
>>> Hi Oded,
>>>
>>> Your three-step reasoning makes sense but, indeed, it should be
>>> experimentally verified. As to the age-related change of neural
>>> oscillations, Art Wingfield believes that the brain "slows down" as we
>>>get
>>> older. Such a slowing-down could also explain the upward AP shift
>>>because
>>> our reference would shift downward. How this central effect squares
>>>with the
>>> peripheral, BM-stiffening effect is unknown but, again, could be
>>>studied in
>>> the lab.
>>>
>>> -Pierre
>>>
>>> On 12/1/12 5:17 AM, "Oded Ghitza" <oghitza@xxxxxx> wrote:
>>>
>>> Hi Pierre,
>>> If (1) you accept Julius's model of pitch perception, (2) interpret --
>>>as he
>>> did -- the central component of the model as a mechanism that adjusts
>>>f0 of
>>> an internal harmonic sieve to the point where the MMSE between the
>>>sieve and
>>> the input pattern is minimum, and (3) assume that such mechanism is
>>>realized
>>> by a neuronal circuitry with oscillations ("rhythms") at the core
>>>(maybe
>>> related to Langer, in the late 80's and in the context of pitch
>>>perception,
>>> who measured "temporal rings" in chicks); then, a possible way to
>>>examine
>>> the phenomenon (whether perceived pitch should go up or down, in
>>> particular), is to look at how the frequency range of neuronal
>>>oscillations
>>> change with age.
>>> --
>>> Oded.
>>>
>> Bob Masta
>>
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