HDTenEightyP/NetNews huggingface dataset:
From: ACKROYD@UTSW.BITNET
Newsgroups: bionet.neuroscience
Subject: end subscription
Date: 17 Nov 92 21:24:00 GMT
Distribution: bionet

Please end my subscription. Thanks A.Ackroyd
From: simonofb@wmavm7.VNET.IBM.COM
Date: Fri, 20 Nov 92 15:46:00 EST
Newsgroups: bionet.neuroscience
Subject: Stribismus
Reply-To: simonofb@wmavm7.VNET.IBM.COM
Organization: IBM
News-Software: Usenet 3.0

I agree with Kate, it seems as though  Mark W. Dubin hit the
nail on the head.  His statements exactly match my experiences.
Unfortunately, that means there is no hope.  I really wonder
what I am missing by seeing things differently (as tests have
shown).

Stereographs do not work for me.  3D movies dont have any effect.
And a picture of a fly my doctor showed me looked fine to me, but
was supposed to look screwed up in some way.  This is how he made
his diagnosis.  Like Kate, I can drive with out a problem, but
certain circumstances cause problems.

Thanks
Robert Simonoff
simonofb@wmavm7.vnet.ibm.com
From: REBECCA@YaleVM.YCC.Yale.Edu (Rebecca Drayer)
Newsgroups: bionet.neuroscience
Subject: Re: (none)
Date: 16 Nov 92 23:57:54 GMT
Organization: Yale University

In article <2B080857.3179@news.service.uci.edu>
mundkur@falcon.eng.uci.edu (Prashanth Mundkur) writes:
 
>	Some questions for which I am looking for answers are
>2) How do you say that a neuron responds to a certain stimulus? What exactly is
>involved when one places electrical electrodes on a cell membrane?
 
I'm only a beginning neuroscience student, but I believe that the researchers
actually put the electrode through the cell membrane.  They measure the
difference in electrical potential between the inside and the outside of the
neuron.  Normally, when the cell is "resting", this potential is very
negative.  (i.e., the inside of the cell is about 70 mV more negative than
the outside.)  When the neuron responds to a stimulus, it can do so by
opening channels permeable to sodium ions.  At that point, sodium ions rush
in and excite the cell by depolarizing it (reducing the potential difference
between the inside and the outside.)
 
Hope this helps.
 
*************************************************************************
Rebecca A. Drayer, EMT        |    Rebecca@Yalevm.YCC.Yale.edu
P.O. Box 6349 Yale Station    |    Computing Assistant
New Haven, CT 06520           |    Silliman College, Yale University
 
Otto: "Don't EVER call me stupid."
Wanda: "No, that would be an insult to stupid people!!"
                                         -A Fish Called Wanda
*************************************************************************
From: drayer-rebecca@yale.edu (Rebecca Drayer)
Newsgroups: bionet.neuroscience
Subject: Re: Vision problem and Virtual Reality
Date: 20 Nov 1992 17:24:05 -0500
Organization: Yale University Science & Engineering UNIX(tm)
NNTP-Posting-Host: minerva.cis.yale.edu

In article <dubin.722276833@spot.Colorado.EDU> dubin@spot.colorado.edu writes:
>LOTS of evidence shows that fixing the strabismus later in life,
>whether surgically, with muscle exercises, or glasses, WILL NOT
>lead to a restoration of stereoscopic depth perception.  Experiments
>on cats and primates have clearly shown that cells in the visual
>cortex are "mis-wired" and can no longer subserve the depth
>perception.  And, there is no known way or treatment that will
>allow the cells to re-connect properly.

That's interesting.  I wonder if it has something to do with
activity-dependent synaptogenesis during development or early life (i.e.,
not enough activity, and the cells won't connect correctly.  This
phenomenon sounds a lot like an experiment done by Wiesel and Hubel in
which newborn monkeys were deprived of vision in one eye for about six
months.  As a result, retinal ganglion cells from that eye appeared to
connect correctly to the lateral geniculate, but the lateral geniculate
didn't connect correctly to visual cortex.  Basically, the animal could
never see properly out of that eye.

(Sorry if everyone already knows this; I just learned about it, and think
it's really neat.  :-))

-- 
Rebecca A. Drayer, EMT-A            |    drayer@minerva.cis.yale.edu
Neurobiology major                  |    Computing Assistant
                                    |    Silliman College, Yale University
From: pck@castle.ed.ac.uk (P C Knox)
Newsgroups: bionet.neuroscience
Subject: Re: Vision problem and Virtual Reality
Date: 23 Nov 92 09:54:26 GMT
Organization: Edinburgh University

spotter@sanger.bio.uci.edu (Steve Potter) writes:

>With all due respect to the ol' professor, Dr. Dubin, dont believe anyone
>who says something can't be done.  Especially when it comes to issues
>of neural plasticity.  Monkeys and cats are different than humans in the
>very important respect that we can follow instructions and intentionally
>carry out excercises that can re-wire out visual system.  For instance
>I have recently successfully trained my eyes to merge images that are
>further apart than my interocular distance.  This requires the eyes to
>diverge, something they never needed to do in our evolutionary history.

>Also, in order to cross-fuse images without using lenses, it is necessary
>to focus at a distance that is different than the point of convergence,
>another behavior that Mother Nature never intended us to do.  This
>can be learned by most people with practice, even full-grown ADULTS
>(but maybe not cats and monkeys).  

But there are surely two separate issues here. Learning "new" eye
movements can clearly be done; indeed Roger Carpenter mentions this in
his excellent book "Movements of the Eyes" (Pion, London). And new eye
movement may allow you to exploit the connections in th visual system.
But new patterns of wiring, particularly the binocular convergence
patterns, do not develop in the adult visual cortex. However, there is
some int4eresting work being done in Frankfurt that suggests that
reintroduction of immature glial cells into an adult cortex does restore
developmental plasticity (published within the last year or two in
"Nature"). If menory serves, NMDA receptors are involved.
	I've found this an interesting thread for another reason. In the
UK strabismus surgery is very common. The objective is to retore
allignment of the eyes to allow the normal cortical wiring to develop.
But in the process, the surgery on the extra-ocular muscles frequently
disturbs the proprioceptive feedback signals the provide. This is enough
to leave deficits in spacial localisation even if stereopsis develops.
The clinical investigations are done by Steinbach in Canada. I'm
interested to see that some of the contributers to this thread talk
about "clumsiness". This could be due to disruptions to spatial visual
processing causeing mislocation of objects and even of limbs  with
respect to external objects. 
	We're about to start some human pilot experiments to invetigate
the role of EOM afferent feedback signals in the control of eye
movement. If anyone's interested let me know and I'll keep you posted.

Paul C Knox
From: simonofb@wmavm7.VNET.IBM.COM
Date: Fri, 20 Nov 92 15:58:26 EST
Newsgroups: bionet.neuroscience
Subject: Re: Vision problem and Virtual Reality
Reply-To: simonofb@wmavm7.VNET.IBM.COM
Organization: IBM
News-Software: UReply 3.0
            <crystal.722283589@glia>

In <crystal.722283589@glia> Crystal writes:
>
>physical clumsiness...
>frequent headaches.  And no, he can not deal with 3-D,
>nor use binoculars
>or microscopes with any success.
>

No on the clumsiness for me, yes on the headaches.  I can use
binoculars and microscopes only if I close one eye.

>While amblyopia (lazy eye) can be a contributing factor to strabismus,
>the eye-patch idea has not been proven to be a cause of later
>strabismus.

So could be genetic, could be eye patch.  I did indeed have an eye
patch, but, being alive, I also have genetics.

>Her condition was treated non-surgically, but I
>forget the details now.

You are saying that there might be a cure of rmy lack 'o 3D vision?

Robert Simonoff
simonofb@wmavm7.vnet.ibm.com
From: T80SMS1@NIU.bitnet
Newsgroups: bionet.neuroscience
Subject: Job announcement
Date: 16 Nov 92 15:00:00 GMT
Distribution: bionet


            POSITION ANNOUNCEMENTS

Northern Illinois University anticipates a
tenure-track ASSISTANT PROFESSOR position for
fall, 1993.  A Ph.D and postdoctoral experience are
required.  Each candidate will be expected to
develop a vigorous externally funded research
program, direct graduate (M.S. and Ph.D) students,
and teach introductory courses for majors and non-
majors.

CELL BIOLOGIST:  The candidate should have research
experience in cell signal transduction, cell growth
control (oncogenes), and/or the cytoskeleton.
Teaching obligations will include an introductory
human anatomy-physiology course and a course in the
candidate's area of expertise.

  Send a letter of interest, curriculum vitae,
brief statement of research goals and teaching
goals, representative reprints, and three letters
of reference by December 31, 1992 to:  Dr. Marvin
Starzyk, Chair, Department of Biological Sciences,
Northern Illinois University, DeKalb, IL 60115-
2861.  Telephone:  815-753-1753.  Northern Illinois
University is an Affirmative Action/Equal
Opportunity Employer.
From: simonofb@wmavm7.VNET.IBM.COM
Date: Thu, 19 Nov 92 16:07:14 EST
Newsgroups: bionet.neuroscience
Subject: Vision problem and Virtual Reality
Reply-To: simonofb@wmavm7.VNET.IBM.COM
Organization: IBM
News-Software: Usenet 3.0

My doctor tells me that I have a vision problem called stribismous
(sp ?) which inhibits my ability to see certain 3 dimensional
aspects of scenes.  I don't really understand all of the nuances.
I have noticed that when I went to Disney World in Florida, there was
a 3D movie theater where you wore 3D glasses and supposedly were
able to see a 2D movie in 3d.  All I saw was a VERY blurry image
that gave me a headache.  I have 2 questions about this condition
which my doctor was not able to answer.

1) What exactly can I expect to perceive differently than others?
- 3D movies obviously that are rendered using the 3D glasses is
  one I know about.
- What about virtual reality scenes where the 3D is generated by
  rapidly flipping between the left and right eye images?
- What other problems should I expect?

2) supposedly this problem was caused by my eye doctor's placing
a patch on my lazy eye for too long a period of time.  Does this
make sense? What did this do to me physically to cause
this problem?

Thanks
Robert Simonoff
simonofb@wmavm7.vnet.ibm.com
From: DSCT@db1.cc.rochester.edu (DAVID SCOTT)
Newsgroups: bionet.neuroscience
Subject: russia with love
Date: 19 Nov 92 04:20:00 GMT
Organization: University of Rochester, Rochester NY
X-News-Reader: VMS NEWS 1.11

I am trying to find the e-mail adress of the institute of experimental
physiology  in St. Petersburg in what used to be the Soviet Union. Any
Help with any part of the adress would be good. either post it, or
preferably mail to dsct@db1.cc.rochester.edu. Thank you in advance.
			Gavin
From: jranta@klaava.Helsinki.FI (Jukka O Ranta)
Newsgroups: bionet.neuroscience
Subject: Stochastic models in neurosci.?
Keywords: Stochastics
Date: 18 Nov 92 15:59:27 GMT
Organization: University of Helsinki

Hello !
I'm a student of mathematics and mainly studying stochastic
processes. I'm looking for some information about applying
stochastic models in neuroscience for my thesis.
I'd be grateful if someone could provide some useful hints
about such things. So, if you know something about applying
stochastic models in neuroscience or where to find more 
information, please mail me. Thanks.

Jukka Ranta
jranta@cc.helsinki.fi
From: mbelmont@sdcc3.ucsd.edu (Matthew Belmonte)
Newsgroups: bionet.neuroscience
Subject: astereopsis (was Re: Vision problem and Virtual Reality)
Keywords: stereopsis stereo-blindness
Date: 21 Nov 92 02:35:15 GMT
Followup-To: bionet.neuroscience
Organization: UCSD Neurosciences

In article <crystal.722283589@glia> crystal@glia.biostr.washington.edu (Crystal)
writes:

>Her post-operative treatment is an eye 
>cream that contains cholinesterase (sp?), an inhibitor to acetylcholine
>in some post-synaptic neuron that somehow strengthens the eye muscles (or
>at least that was what she told me - this could be in error - please 
>correct it)

Acetylcholinesterase catalyses the degradation of acetylcholine (the
neurotransmitter at the neuromuscular junction) into acetate and choline.  It
occurs naturally in the synaptic cleft; without it, the postsynaptic cell would
stay depolarised for a very long time.  The addition of acetylcholinesterase
would weaken the muscle, not strengthen it.  Since the extraocular muscles are
set up as opponents, though, I guess this would have the desired effect since
it'd lower the difference in tension between the two recti.

As for lack of stereopsis, it's extremely common, and many (if not most) people
who lack stereopsis don't know that they lack stereopsis.  I can't remember
where I read it, but I seem to remember some text mentioning that about 10% of
the population doesn't have stereo vision.  In most activities this makes almost
no difference; the visual system is very good at inferring the third dimension
from two-dimensional cues such as relative size, shading, and obscurement.  The
revelation that a person lacks stereopsis usually evokes surprise and a sense of
wonder about what it must be like to see `true' 3-D.

I've always had difficulty getting my eyes to point at the same place---often
when I'm reading and especially when I'm tired---and for a long time I wondered
what I was doing wrong because I never could get any of those nifty stereograms
to work.  It was only when I started studying neuroscience that I realised that
I really have no 3-D vision.  Groovy, huh?  (The eye-pointing problem seems to
have got worse as I've got older---too many late nights with the neuroscience
literature :-)
-- 
Matthew Belmonte	mbelmonte@ucsd.edu
`The Bohemian Kingdom' - Risley Residential College for the Creative and
Performing Arts, Ithaca, New York
From: MCCAINKW@DUVM.OCS.DREXEL.EDU (kate McCain)
Newsgroups: bionet.neuroscience
Subject: strabismus
Date: 20 Nov 92 18:55:26 GMT
Distribution: bionet

I found Mark Dubin's posting interesting and educational.  I have always
wondered why I have (apparently) good depth perception [I always do well
on the optometrist's polarized light tests and driving tests etc.] but still
"see double*"  Piecing his comments together with those of my opinionated
optometrist -- my brain is just not processing the two visual images
(at depth) the same way that most people's brains do. I must get depth
perception via some kind of parallax??  Following an early diagnosed "lazy
eye" (and extreme farsightedness) I have worn glasses since age 3.5 yrs,
bifocals since 15, trifocals since 37 and am now wearing progressives -- plus
early exercises, atropine treatments, and surgery at 14 to "improve fusion."

*at distance -- close vision seems to be ok.

I can certainly believe the "miswiring" characterization -- but if the
"exercise won't work" statement is correct -- then why do optometrists
recommend them? Are there similar conditions where eye muscles _can_ be
exercised to improve vision??

Kate McCain                       bibliometrics R us
College of Information Studies

mccainkw@duvm.ocs.drexel.edu
From: mundkur@falcon.eng.uci.edu (Prashanth Mundkur)
Newsgroups: bionet.neuroscience
Subject: (none)
Date: 16 Nov 92 20:45:11 GMT
Organization: University of California, Irvine

Hi!
	I am looking for a text/review article/papers on the basic techniques
used in neuroanatomy and neurophysiology. What I am interested in is NOT the 
conclusions of the various experiments that are conducted as part of research
in these areas, but the experimental techniques themselves. 
	Some questions for which I am looking for answers are
1) How do you conduct an experiment that traces the path of an axon for over
50 cms? 
2) How do you say that a neuron responds to a certain stimulus? What exactly is
involved when one places electrical electrodes on a cell membrane?
3) Drawing conclusions about a neuron's functional behaviour from brain lesion
experiments surely is very error-prone. What are the mistakes one should not
make when drawing conclusions from such experiments?
4) When one sets up a "mathematical" model of the operation of a set of neurons
in a particular part of the nervous system, what does one normally take into 
account, and what does one assume to be irrelevant to the modeling objective?
	I should have mentioned earlier that I am not even remotely a 
neuroscience student, and so I will not be able to understand common abbreviations
that may be in use in the neuroscience community for technical terms/journals/books.
I need the above information for a project in a course on "Models of the Brain".
Thanks for any advice and/or pointers to literature.
--Prashanth.
From: pinto@neurocog.lrdc.pitt.edu (David Pinto)
Newsgroups: bionet.neuroscience
Subject: Re: (none)
Date: 23 Nov 92 19:34:16 GMT

In article <astlab3.1@uci.edu>, astlab3@uci.edu writes:
|> In article <2B080857.3179@news.service.uci.edu> mundkur@falcon.eng.uci.edu (Prashanth Mundkur) writes: 
|> >4) When one sets up a "mathematical" model of the operation of a set of neurons
|> >in a particular part of the nervous system, what does one normally take into 
|> >account, and what does one assume to be irrelevant to the modeling objective?
 |> [comments deleted]
|> >Thanks for any advice and/or pointers to literature.
|> >--Prashanth.


|> 4)  Currently the connectionist paradigm is the most popular for modelling
|> 	the functioning of the brain.  The connectionist's bible is 
|> 	"Parallel distributed processing" by some guys at San Diego that
|> 	 I can't recall right now.

If Neurons are being modelled in very large groups, or as node points, without
taking the specifics of each neuron into account, then connectionist models
are the current favorite.

For models of one, two, three or maybe a few more neurons, compartmental models
seem to be prefered.  
   Compartmental models break each neuron down into a series of linked segments
e.g. soma, axon, dendrite branches.  The electrical properties of each segment
can then be represented with a simple (sometimes not so simple) circuit and a 
few equations (e.g. Hodgkin/Huxley, Fitzhugh-Nagumo, etc.).  The segments can
then be linked together to behave as a whole neuron.
   Some really impressive software is around which takes care of all this and
has some nifty graphic displays of things like action potential propagation and
potential spread through dendritic arbors.  Genesis and the Hines Neuron Simulator
come to mind.
   A good reference would be another book by Gorden Shephard "The Synaptic
Organiztion of the Brain" esp the Appendix.  Also the Segev book mentioned 
by someone else, and anything by Wilfred Rall.

As far as what sort of things are taken into account for such models (i.e. 
single neuron), mainly the geometry (obviously) as well as electrical
parameters such as the specific membrane capacitance (generally taken as a
constant 1 uF (micro-Farad), and the input resistance of the membrane.  
    Actually, rather than input resistance, what is needed is both axial
resistance (the resistance down the 'barrel' of the axon, and the specific
membrane resistance.  These can be calculated, however, with knowledge 
of the cell geometry (diameter, lengths, etc.), and the input resistance.

BTW Parallel Distributed Processing is by McClelland & Rumelhart.

---------------------------------------------------------------------------
"Imagine No Limits" - Company slogan? or mathematicians nightmare?
---------------------------------------------------------------------------
From: jdevlin@pollux.usc.edu (Joseph T. Devlin)
Newsgroups: bionet.neuroscience
Subject: Alzheimer's disease
Date: 22 Nov 1992 14:18:53 -0800
Organization: University of Southern California, Los Angeles, CA
Distribution: world
NNTP-Posting-Host: pollux.usc.edu
Summary: Effect of neurofibrillary tangles and amyloid plaque

  In Alzheimer's disease two of the neuropathological conditions
mentioned most frquently are the presence of neurofibrillary
tangles and overproduction of beta-amyloid leading to plaque
formation.  As often as I see this information, however, I never
have seen any suggestions as to how these affect the normal
processing characteristics of a neuron.  Presumably since both
are pathological they have some affects which might very well differ
between cell types or even among cell types but I haven't come
across this information if that is so.
  For tangles I would assume this might affect process lengths
if only because they damage cytoskeletal elements.  I have
no idea what effect plaques might have.  
  Can anyone answer any of these questions or perhaps point me
towards appropriate references?  In the event these are still
unanswered questions would anyone care to speculate on the
effects?  
  Thank you all in advance. 

							- Joe

*************************************************************************
Joseph Devlin                      * email: jdevlin@pollux.usc.edu
University of Southern California  *
Department of Computer Science     * "The axon doesn't think.
Los Angeles, CA 90089              *  It just ax."  George Bishop
*************************************************************************


Newsgroups: bionet.neuroscience
From: Mark W. Dubin
Subject: Re: Vision problem and Virtual Reality
Originator: dubin@spot.Colorado.EDU
Reply-To: dubin@spot.colorado.edu
Organization: Univ. of Colorado-Boulder
Date: Fri, 20 Nov 1992 16:27:13 GMT

I have some accurate info and a conjecture:

Ambylopia due to strabismus, if not dealt with prior to about age
eight often leads to a loss of what is called stereoscopic depth
perception.  That is manifested as the inability to fuse the kind
of 3D images seen with stereo viewers and those famous movie glasses.
LOTS of evidence shows that fixing the strabismus later in life,
whether surgically, with muscle exercises, or glasses, WILL NOT
lead to a restoration of stereoscopic depth perception.  Experiments
on cats and primates have clearly shown that cells in the visual
cortex are "mis-wired" and can no longer subserve the depth
perception.  And, there is no known way or treatment that will
allow the cells to re-connect properly.

I am now conjecturing that the virtual reality situation is homologous
to the movie glasses, and that depth will not be seen, but I'm not 
sure.  There may be other cues that allow some depth perception.

I write as one who has studied the development of the vertebrate
visual system as my area of specialization for over 20 years.

--the ol' professor
From: spotter@banting.bio.uci.edu (Steve Potter)
Subject: Re: Vision problem and Virtual Reality
Newsgroups: bionet.neuroscience
Organization: University of California, Irvine
Date: 20 Nov 92 07:12:34 GMT

Strabismus, a kind of cross-eyedness, is a muscular problem.  A
brother and a sister of mine both had it bad ("lazy-eye") when
they were little.  Bro wore a patch all thru kindergarten and
that helped a lot. Sis wore glasses all her life, and is better,
but still cross-eyed without glasses.  Both wear contacts now, and
both are fully able to enjoy my 3D photographs, a hobby of mine.  Smoe
Some bad cases are corrected by surgery.  I would opt for eye exercises
instead.  Depth perception, aside from being fun in 3D movies,and
VR, can save your life in any situation where you are moving and avoiding
things (they may be moving while you are still, too.)  One-eyed
people (and strabismics, I suppose) can get around their lack of depth
perception from parallax by getting "motion parallax" the way a pidgeon
does, by moving the head back and forth.  They probably have other,
possibly unconscious tricks too.

Eye muscles can be trained and strengthened like any other muscles,
so look into that if you want to gain full use of your visual system.

Steve Potter
UC Irvine Psychobiology
spotter@darwin.bio.uci.edu



Newsgroups: bionet.neuroscience