[bionet.neuroscience] Attention, Neurochemically Speaking

tv@sei.cmu.edu (T. VanderHeyden) (04/12/91)

Attention in humans is quite a varied thing. Children notice different 
things than adults do. People taking acid might fall in love with their 
bathroom toilets and spend the whole trip in the bathroom, while a 
seven-foot-tall tattooed skinhead in a knit minidress might escape notice 
in some sections of New York City.

What's the chemical action going on here (LSD notwithstanding)? Is there a 
chemical released by some part of the brain that, when present, causes one 
to pay more attention to details and, when absent, causes one to ignore 
certain details? What's been written on this subject?

Todd VanderHeyden

brp@bandit.berkeley.edu (Bruce Raoul Parnas) (04/12/91)

In article <23933@as0c.sei.cmu.edu> tv@sei.cmu.edu (T. VanderHeyden) writes:
>
>What's the chemical action going on here (LSD notwithstanding)? Is there a 
>chemical released by some part of the brain that, when present, causes one 
>to pay more attention to details and, when absent, causes one to ignore 
>certain details? What's been written on this subject?

well, any reader of the Hitchhiker's Guide to the Galaxy has a clue to the
answer.  Attention is hindered by the presence of a Somebody Else's
Problem (SEP) field.  When one of these is emitted, the issue is treated by
all present as somebody else's problem, and is ignored.  This is used by
certain alien species to escape unnoticed as they visit Earth.  Attention,
coversely, must be related to the lack of such a field.

>
>Todd VanderHeyden

sorry, but i just had to,


bruce
(brp@bandit.berkeley.edu)
bruce
(brp@bandit.berkeley.edu)

peretz@grad1.cis.upenn.edu (Samuel R. Peretz) (04/12/91)

In article <23933@as0c.sei.cmu.edu>, tv@sei.cmu.edu (T. VanderHeyden) writes:
|>Attention in humans is quite a varied thing. Children notice different 
|>things than adults do. People taking acid might fall in love with their 
|>bathroom toilets and spend the whole trip in the bathroom, while a 
|>seven-foot-tall tattooed skinhead in a knit minidress might escape notice 
|>in some sections of New York City.
|>
|>What's the chemical action going on here (LSD notwithstanding)? Is there a 
|>chemical released by some part of the brain that, when present, causes one 
|>to pay more attention to details and, when absent, causes one to ignore 
|>certain details? What's been written on this subject?
|>
|>Todd VanderHeyden
            
One hypothesis is that attention is related to synchronized oscillations
in certain brain regions.  I can't remember the exact reference, but there
was a paper by Francis Crick a couple years back regarding this
"searchlight" hypothesis of attention.  I think the brain region discussed
in that particular paper was the hypothalamus.

						--Sam

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	< Samuel R. Peretz			      		>
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	< University of Pennsylvania		 ------- 	>
	< Inst. for Neurological Sciences	| 0   0 |	>
	< (215) 898-8048			|   V   |	>
	< srp@vision5.anatomy.upenn.edu		|  ===  |	>
	< aka sam@retina.anatomy.upenn.edu	 -------	>
	< aka peretz@grad1.cis.upenn.edu			>
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rowe@pender.ee.upenn.edu (Mickey Rowe) (04/12/91)

In article <40953@netnews.upenn.edu> peretz@grad1.cis.upenn.edu (Samuel R. Peretz) writes:

>One hypothesis is that attention is related to synchronized oscillations
>in certain brain regions.  I can't remember the exact reference, but there
>was a paper by Francis Crick a couple years back regarding this
>"searchlight" hypothesis of attention.  I think the brain region discussed
>in that particular paper was the hypothalamus.

That would be thalamus, Sam.  There are actually a couple of papers
that go sort of along these lines (ask Jim Cummings for some of
them; he used one of these papers for a journal club last fall.)  

From what I recall, there is a bit of controversy about what exactly
attention is.  You might want to do an author search on Michael Posner
and (David?) Gevins.  These two people seem to have pretty much
opposite opinions on the matter.  Posner does PET scans on humans and
lesion studies in monkeys--he's found a couple of cortical areas that
he believes are related to attention.  Some of his experiments
indicate that attention is an active process that (at least for visual
stimuli) can be localized in space.  In his models shifts in attention
involve three processes--disengaging, moving and re-engaging.  Some of
his monkey experiments indicate that you can actually measure the
speed at which the attentional beacon moves across space as the monkey
shifts its resources from one target to another.

Gevins has reached a completely different set of conclusions in his
experiments on air force fighter pilots.  He does EEG recordings with
up to 144 scalp electrodes on subjects as they perform various tasks.
He feels that attention is not related to any particular place on
cortex, but rather is related to overall pattern of activation.

You'll note that both of these people work pretty much exclusively on
cortex.  Sam is right about the fact that thalamus is often implicated
in attention, since it seems to modulate what gets to what parts of
cortex.  There are some ideas about the role of thalamus in attention,
but other than the reference to Crick, and my next reference to
Sherman, I'm not as familiar with this work.

If you really want to get into some deeper electrophysiology you might
want to check out Murray Sherman who has been trying to elucidate a
mechanism whereby the lateral geniculate nucleus modulates signals
from retinal ganglion cells in order to highlight areas that might be
of behavioual interest.  At the other end (human psychology) you might
want to look into Triessman (sp?).  I know of some of her work in
object perception, but a reputable source (Jenni Groh, a fellow
graduate student) claims that she has done some work on attention as
well.  It seems to me that someone else from NIH gave a talk here
within the past couple of years, and that he spoke about attentional
mechanisms in visual perception.  I'm pretty sure that it was Peter
Schiller, but whoever it was you should be able to track them down in
references by Posner.

You'll probably find work on the area of attention somewhat
dissappointing, because it's one of those things that you can talk
with anyone on the street and they'll know just what you're talking
about, but if you try to pin it down in some way that you can do
experiments with it you'll find that the concept is pretty nebulous.
It is an interesting area to look into, though if you have the
fortitude to do some heavy reading...

>
>						--Sam
>
>	<=======================================================>
>	< Samuel R. Peretz			      		>
>	< 126 Anatomy/Chemistry Bldg.		   \ /  	>
>	< University of Pennsylvania		 ------- 	>
>	< Inst. for Neurological Sciences	| 0   0 |	>
>	< (215) 898-8048			|   V   |	>
>	< srp@vision5.anatomy.upenn.edu		|  ===  |	>
>	< aka sam@retina.anatomy.upenn.edu	 -------	>
>	< aka peretz@grad1.cis.upenn.edu			>
>	<=======================================================>


Mickey Rowe   (from the other side of campus--the uglier building
               that's much harder to get lost in)

rowe@pender.ee.upenn.edu

eopa27@castle.ed.ac.uk (Dr D R T Keeble) (04/12/91)

In article <40969@netnews.upenn.edu> rowe@pender.ee.upenn.edu (Mickey Rowe)
writes:

>of behavioual interest.  At the other end (human psychology) you might
>want to look into Triessman (sp?).  I know of some of her work in
>object perception, but a reputable source (Jenni Groh, a fellow
>graduate student) claims that she has done some work on attention as
>well.  It seems to me that someone else from NIH gave a talk here

A standard reference is: 

A Treisman, 
"Features and Objects: The Fourteenth Bartlett Memorial Lecture"
The Quarterly Journal of Experimental Psychology, 1988 40A (2) 201-237.

Many of her experiments consist of target searches in a field of distractors.
Eg, locating a vertical line in an array of tilted lines. Such tasks are
clearly related to attention.

David Keeble,

Vision-Lab, Department of Pharmacology, University of Edinburgh

niels@vis.toronto.edu (Niels daVitoria Lobo) (04/12/91)

In addition to Crick and Treisman one should look at work by Tsotsos 
[reference: Tsotsos, J.K., ``Analyzing Vision at the Complexity Level'', 
Behavioral and Brain Sciences 13-3, p423 - 445, 1990.]

In this and subsequent work a detailed computational model of visual attention 
is described.  The theory integrates previous psychophysical findings and 
predicts new ones.  Very interesting stuff.