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Re: The climb of absolute pitch


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 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
>            D A Q A R T A
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