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Re: The climb of absolute pitch
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.
Dept. of Communication Sciences and Disorders
2240 Campus Dr.
Evanston, IL 60208
On 12/3/12 7:38 PM, "Kevin Austin" <kevin.austin@xxxxxxxxxxxx> wrote:
>I had been led to believe that frequency was encoded along the BM, and
>that pitch was the interpretation of this stimulus.
>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
>>> older. Such a slowing-down could also explain the upward AP shift
>>> our reference would shift downward. How this central effect squares
>>> peripheral, BM-stiffening effect is unknown but, again, could be
>>> the lab.
>>> 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 --
>>> did -- the central component of the model as a mechanism that adjusts
>>> an internal harmonic sieve to the point where the MMSE between the
>>> the input pattern is minimum, and (3) assume that such mechanism is
>>> by a neuronal circuitry with oscillations ("rhythms") at the core
>>> related to Langer, in the late 80's and in the context of pitch
>>> who measured "temporal rings" in chicks); then, a possible way to
>>> the phenomenon (whether perceived pitch should go up or down, in
>>> particular), is to look at how the frequency range of neuronal
>>> change with age.
>> Bob Masta
>> D A Q A R T A
>> Data AcQuisition And Real-Time Analysis
>> Scope, Spectrum, Spectrogram, Signal Generator
>> Science with your sound card!