Re: Pitch orientation-discriminating feature detectors? (Al Bregman )

Subject: Re: Pitch orientation-discriminating feature detectors?
From:    Al Bregman  <al.bregman(at)MCGILL.CA>
Date:    Tue, 24 Sep 2002 14:16:09 -0400

Dear Daniel,

On what scale were the frequency excursions?  If it was a
log-frequency scale, as I suspect it was, it is possible that the
difference would disappear or be reversed if you swept up and
down on a linear scale.  What is the justification for the scale
that you actually did use for the excursions?

Al
-------------------------------------------------
Albert S. Bregman, Emeritus Professor
Dept of Psychology, McGill University
1205 Docteur Penfield Avenue
Montreal, QC, Canada H3A 1B1

Office:
     Phone:  +1 (514) 398-6103
     Fax: +1 (514) 398-4896
Home phone & Fax: +1 (514) 484-2592
Email:   al.bregman(at)mcgill.ca
-------------------------------------------------


----- Original Message -----
From: "Daniel Pressnitzer" <Daniel.Pressnitzer(at)IRCAM.FR>
To: <AUDITORY(at)LISTS.MCGILL.CA>
Sent: 24-Sep-02 1:46 PM
Subject: Re: Pitch orientation-discriminating feature detectors?


> Dear Eliot,
>
> There is a perceptual asymmetry that is linked to the direction
of
> pitch movement. Frequency peaks (upward-then-downward frequency
> modulation) are more salient and produce much lower difference
limens
> than frequency troughs (downward-then-upward FM). This has been
> described in detail by Demany and colleagues in a series of
studies
> published in JASA (see refs below).
>
> We are in fact starting a project to record cortical activity
> associated with FM peaks and troughs, using
magnetoencephalography --
> together with Laurent Demany and Andre Rupp. What we see up to
now is
> that the source waveforms in response to FM peaks consistently
display
> longer N1 latencies and larger N1-P2 amplitudes, when compared
to
> responses to matched FM troughs.
>
> Such an asymmetry might have something to do with previous
reports of
> EEG recordings examining upward vs. downward frequency glides.
For
> instance, Ruhm (1971) showed that upward glides produce bigger
and
> later N1-P2 responses than downward glides.
>
> The next question is of course why would it be useful in the
real
> world to process differently upward vs. downward frequency
> movements...
>
>
> Cheers,
>
> Daniel
>
> ---
>
> (at)Article{demany94,
>   author =       {Demany, L. and McAnally, K.},
>   title = {The perception of frequency peaks and troughs in
wide
>   frequency modulations},
>   journal =      {J. Acoust. Soc. Am.},
>   year =         1994,
>   volume =       96,
>   pages =        {706-715}
> }
>
> (at)Article{demany95a,
>   author =       {Demany, L. and Clément, S.},
>   title = {The perception of frequency peaks and troughs in
wide
>   frequency modulations. II. Effects of frequency register,
stimulus
>   uncertainty and intensity},
>   journal =      {J. Acoust. Soc. Am.},
>   year =         1995,
>   volume =       97,
>   pages =        {2454-2459}
> }
>
> [there are two other Demany and Clément papers in JASA, 1995
and 1997]
>
> (at)Article{ruhm71,
>   author =       {Ruhm, H. B.},
>   title = {Directional sensitivity and laterality of
electroencephalic
>   responses evoked by acoustic sweep frequencies},
>   journal =      {J. Auditory Res.},
>   year =         1971,
>   volume =       11,
>   pages =        {9-16}
> }
>