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Re: Is there considerable phase locking up to 6 kHz?
Richard F. Lyon wrote:
Now that I've read Eckard Blumschein's note about how maybe "Pitch
apparently relates to a kind of autocorrelation that is not based on
phase locking," I think I need to clarify Jan Schnupp's answer in
relation to Hi Cheng-Gia's question.
It is fair to say that "most auditory physiologists would be very
surprised if any mammal was found to phase lock appreciably to
frequencies above 4 kHz." But this should NOT be interpreted to mean
that auditory neurons with a CF above 4 kHz will not show accurate
synchrony to high-frequency complexes with a lower pitch. No phase
locking to frequencies above 4 kHz should be re-phrased as no phase
locking to sine waves above 4 kHz.
Richard is of course absolutely correct about this. If you were to play,
say, an 8kHz carrier tone that was amplitude modulated at 100 Hz then
you would get the 8kHz CF fibres in the auditroy nerve happily phase
locking to the 100 Hz modulator. I'm not sure whether that helps us with
Cheng-Gia's original problem though, as, if I remember correctly, all
three of his tone complexes should have 400 Hz beat frequencies, and
while these beat frequencies should be encoded through temporal (phase
locking) features, the fundamental beat frequency should stay the same.