There are 3 messages totalling 184 lines in this issue.
Topics of the day:
1. Integration of ITD information (3)
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Date: Mon, 10 Oct 2005 19:22:59 +0200
From: Bernhard Laback <Bernhard.Laback@xxxxxxxxxx>
Subject: Integration of ITD information
Dear list,
Is there any evidence for integration of interaural time difference
(ITD) information across frequency channels in ITD detection /
discrimination tasks? More specifically, are ITD JNDs lower for a
broadband stimulus compared to any narrowband stimulus within the
spectral range covered by the broadband stimulus?
Of course, I assume that the overall intensity is held constant.
I would appreciate any hint,
With best regards,
Bernhard Laback
--
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Bernhard Laback, Ph.D.
Acoustics Research Institute
Austrian Academy of Sciences
Reichsratsstrasse 17
A-1010 Wien
Austria
Tel.: 0043-1-4277-29514
Fax.: 0043-1-4277-9295
http://www.kfs.oeaw.ac.at/
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Date: Mon, 10 Oct 2005 19:03:19 +0100
From: Jan Schnupp <jan.schnupp@xxxxxxxxxxxxxxxx>
Subject: Re: Integration of ITD information
I must admit that I don't know the psychophysics literature on that, but
from the Physiology point-of-view I would be surprised if there was much
across-frequency-band integration in ITD processing. The reason for this
is that ITDs must be inferred from inter-aural-phase differences as they
are encoded in spike intervals in the auditory nerve, and these are
different in different frequency bands and depend on the cochlear
filtering as much as on the stimulus. Imagine you play a loud click into
the ears. The 100 Hz place of the cochleas might ring in response to
that stimulus at 100Hz, producing short trains of action potentials at
10 ms intervals, while the 250 Hz location might ring at 250 Hz,
producing 4 ms spike interval trains. Except for the first spike, these
spike trains won't "line up", and comparing the 250 Hz band in the left
ear with the 100 Hz band in the right ear cannot give you an unambiguous
answer about the ITD. That's at least how I think about these things
when I ask myself why the medial superior olive, where ITD extraction is
thought to take place, is said to exhibit a very tight tonotopic
organisation. If there was much to be gained by cross-frequency channel
integration, one might expect the MSO not to exhibit such clearly
defined and separated frequency channels. (However, I might be wrong
about all this, so if some other list members do quote some good
psychophysical evidence for cross-frequency integration, then listen to
them and not to me!)
Regards,
Jan
Bernhard Laback wrote:
Dear list,
Is there any evidence for integration of interaural time difference
(ITD) information across frequency channels in ITD detection /
discrimination tasks? More specifically, are ITD JNDs lower for a
broadband stimulus compared to any narrowband stimulus within the
spectral range covered by the broadband stimulus?
Of course, I assume that the overall intensity is held constant.
I would appreciate any hint,
With best regards,
Bernhard Laback
--
Dr Jan Schnupp
University Laboratory of Physiology
Parks Road - Oxford OX1 3PT
Tel +44-1865-272513
email: jan@xxxxxxxxxxxxxxxx
http://www.physiol.ox.ac.uk/~jan/
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Date: Tue, 11 Oct 2005 03:38:14 +0100
From: David Magezi <David.Magezi@xxxxxxxxxxxxx>
Subject: Re: Integration of ITD information
Bernhard Laback wrote:
Dear list,
Is there any evidence for integration of interaural time difference
(ITD) information across frequency channels in ITD detection /
discrimination tasks? More specifically, are ITD JNDs lower for a
broadband stimulus compared to any narrowband stimulus within the
spectral range covered by the broadband stimulus?
Of course, I assume that the overall intensity is held constant.
I would appreciate any hint,
With best regards,
Bernhard Laback
That is an interesting question. I would recommend the following
papers; Anyone know of any other relevant ones?
Title: Effects of interaural frequency difference on binaural fusion
evidenced by electrophysiological versus psychoacoustical measures
Author(s): Zhou JX, Durrant JD
Source: JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 114 (3): 1508-1515
SEP 2003
Title: THE COMBINATION OF INTERAURAL INFORMATION ACROSS FREQUENCIES -
LATERALIZATION ON THE BASIS OF INTERAURAL DELAY
Author(s): DYE RH
Source: JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 88 (5): 2159-2170
NOV 1990
Sens Processes. 1976 Dec;1(2):109-26.
Critical band in auditory lateralization.
Scharf B, Florentine M, Meiselman CH.
--
*****************************************
David A Magezi BA BM BChir
PhD Student
MRC Institute of Hearing Research
University Park
Nottingham University
Nottingham
NG7 2RD
United Kingdom
T: +44 (0)115 951 8508 ext. 203
F: +44 (0)115 951 8503
E: david.magezi@xxxxxxxxxxxxx
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End of AUDITORY Digest - 9 Oct 2005 to 10 Oct 2005 (#2005-208)
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