"Kalman Rubinson" wrote in message
...
On Sat, 27 May 2006 09:44:11 -0400, "Robert Morein"
wrote:
How about this:
http://illumin.usc.edu/article.php?articleID=45&page=3

If the brain can localize based upon differential delays as small as 10
us,

This is highly unlikely and not supported by reference.

Kal

From http://www.physiol.ox.ac.uk/~raac/pd...aa_curBiol.pdf

"Humans can discriminate ITDs as small as 10-20 ?s [3] - an astonishing
achievement given that the duration of an
action potential is two orders of magnitude greater than this."

From http://www.pubmedcentral.gov/article...gi?artid=34336
" But even a sound coming directly from one side reaches the near ear only
600 ?s earlier than the far one, an interval comparable to the duration of a
single action potential. Our finest discrimination of a source's position
involves measurement of interaural time delay with a precision of less than
20 ?s-a seemingly impossible feat that we reflexively perform dozens of
times a day."

Interesting note on the speed of cilial response:
http://www.hhmi.org/news/coreydp.html

"Within 5 to 10 microseconds of this motion, channels in the hair cell open
and allow ions to enter - the first step in sending a sound signal to the
brain.

According to Corey, the rapidity of this response - which is as much as
1,000 times faster than the opening of similar channels in the eye in
response to light - indicated to scientists that the channel must respond
directly to the mechanical stimulus, rather than relying on a signal from
another molecule. The speed of the response was determined more than 20
years ago in the laboratory of HHMI investigator A. James Hudspeth - but
since that time, no one had been able to identify the channel protein."

I need to follow up on the psychophysical info but the physiology
seems to make it unlikely that there is temporal (rather than a phase)
discrimination of such brevity, an aspect acknowledged in the review.

Kal


On Sun, 28 May 2006 10:46:03 -0400, "Robert Morein"
wrote:


"Kalman Rubinson" wrote in message
.. .
On Sat, 27 May 2006 09:44:11 -0400, "Robert Morein"
wrote:
How about this:
http://illumin.usc.edu/article.php?articleID=45&page=3

If the brain can localize based upon differential delays as small as 10
us,

This is highly unlikely and not supported by reference.

Kal

From http://www.physiol.ox.ac.uk/~raac/pd...aa_curBiol.pdf

"Humans can discriminate ITDs as small as 10-20 ?s [3] - an astonishing
achievement given that the duration of an
action potential is two orders of magnitude greater than this."

From http://www.pubmedcentral.gov/article...gi?artid=34336
" But even a sound coming directly from one side reaches the near ear only
600 ?s earlier than the far one, an interval comparable to the duration of a
single action potential. Our finest discrimination of a source's position
involves measurement of interaural time delay with a precision of less than
20 ?s-a seemingly impossible feat that we reflexively perform dozens of
times a day."

Interesting note on the speed of cilial response:
http://www.hhmi.org/news/coreydp.html

"Within 5 to 10 microseconds of this motion, channels in the hair cell open
and allow ions to enter - the first step in sending a sound signal to the
brain.

According to Corey, the rapidity of this response - which is as much as
1,000 times faster than the opening of similar channels in the eye in
response to light - indicated to scientists that the channel must respond
directly to the mechanical stimulus, rather than relying on a signal from
another molecule. The speed of the response was determined more than 20
years ago in the laboratory of HHMI investigator A. James Hudspeth - but
since that time, no one had been able to identify the channel protein."

I just found an interesting review article:
http://www.physiol.ox.ac.uk/~raac/pd...aa_curBiol.pdf
I get the impression that you are correct, that these are phase differences.
If this is the case, it is rather misleading to refer to "arrival time
differences." In the case of a steady state tone, it doesn't arrive, it is
simply present, and an accurate term for the faculty would be phase
discrimination. I haven't found any web references to the localization of
impulsive sounds, as opposed to steady-state tones.

If you find anything on localization of impulsive sounds, please post.

"Kalman Rubinson" wrote in message
...
I need to follow up on the psychophysical info but the physiology
seems to make it unlikely that there is temporal (rather than a phase)
discrimination of such brevity, an aspect acknowledged in the review.

Kal


On Sun, 28 May 2006 10:46:03 -0400, "Robert Morein"
wrote:


"Kalman Rubinson" wrote in message
. ..
On Sat, 27 May 2006 09:44:11 -0400, "Robert Morein"
wrote:
How about this:
http://illumin.usc.edu/article.php?articleID=45&page=3

If the brain can localize based upon differential delays as small as 10
us,

This is highly unlikely and not supported by reference.

Kal

From http://www.physiol.ox.ac.uk/~raac/pd...aa_curBiol.pdf

"Humans can discriminate ITDs as small as 10-20 ?s [3] - an astonishing
achievement given that the duration of an
action potential is two orders of magnitude greater than this."

From http://www.pubmedcentral.gov/article...gi?artid=34336
" But even a sound coming directly from one side reaches the near ear only
600 ?s earlier than the far one, an interval comparable to the duration of
a
single action potential. Our finest discrimination of a source's position
involves measurement of interaural time delay with a precision of less
than
20 ?s-a seemingly impossible feat that we reflexively perform dozens of
times a day."

Interesting note on the speed of cilial response:
http://www.hhmi.org/news/coreydp.html

"Within 5 to 10 microseconds of this motion, channels in the hair cell
open
and allow ions to enter - the first step in sending a sound signal to the
brain.

According to Corey, the rapidity of this response - which is as much as
1,000 times faster than the opening of similar channels in the eye in
response to light - indicated to scientists that the channel must respond
directly to the mechanical stimulus, rather than relying on a signal from
another molecule. The speed of the response was determined more than 20
years ago in the laboratory of HHMI investigator A. James Hudspeth - but
since that time, no one had been able to identify the channel protein."