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Re: / Jont, Al, Peter



In my last note, I responded to Jont and raised issues similar to what
Al does in his last note (and Kevin raised first with his scratchy
record analogy): The auditory system does not seem to be doing a great
job integrating temporal information across different frequency channels.
The following papers address the problem from the standpoint of the
psychophysics of envelope processing (in the range of 1 to 100-or-so milli-
seconds, depending on how you define the intervals).

   Divenyi, P. L., & Danner, W. F. (1977). Discrimination of time intervals
   marked by brief acoustic pulses of various intensities and spectra.
   Perception and Psychophysics, 21, 125-142.

   Divenyi, P. L., & Sachs, R. M. (1978). Discrimination of time intervals
   bounded by tone bursts. Perception and Psychophysics, 24, 429-
   436.

   Formby, C., Sherlock, L.P., & Forrest, T.G. (1996). An asymmetric roex filter
   model for describing detection of silent temporal gaps in sinusoidal
   markers. Auditory Neuroscience, 3(1), 1-20.

I also suggested about a week ago that it is possible to estimate the
delay between the periphery and the structure (quite probably cortical)
at which the time intervals are computed, by looking at the distributions in
a detection/discrimination task. The underlying models are quite simple
and pretty much taken for granted by the psychoacoustics community. What
results in the above papers suggest is that there must be an extra stage
of processing between the one running the internal timer **within** a
single channel/stream and the one timing events when the markers are in
different channels/streams. Does anybody know if this or similar problems
have been looked at by stochastic modellers? By physiologists?
Peter (Cariani)?

        Pierre

PS: Chuck, Lloyd's coincidence detector is also frequency-specific.