From: sfm@manduca.neurobio.arizona.edu (Stephen Matheson)
Newsgroups: talk.abortion
Subject: Re: Spoken Like a True ProLifer
Date: 12 Jan 93 21:42:29 GMT
Organization: University of Arizona UNIX Users Group

From article <JBATES.93Jan12132814@pinocchio.encore.com>,
by jbates@encore.com (John W. Bates):

> In article <1993Jan12.040001.6011@mnemosyne.cs.du.edu>
> mcochran@nyx.cs.du.edu (Mark A. Cochran) writes:
>>In article <1993Jan11.065635.16749@organpipe.uug.arizona.edu>
>>sfm@manduca.neurobio.arizona.edu (Stephen Matheson) writes:

Even number of >'s = Mark Cochran (mcochran@nyx.cs.du.edu)
Odd number of >'s  = Steve Matheson (sfm@manduca.neurobio.arizona.edu)

>>>>>> Given that myelination is necessary for proper
>>>>>> conduction of impulses in the brain

>>>>>Just how "given" is this?  Before myelination, aren't most fibers
>>>>>nevertheless conducting impulses, albeit much more slowly than after
>>>>>myelination?  I'm going to go check this, but I'm rather sure at this
>>>>>point that myelination speeds conduction rather than making it possible
>>>>>(that's the job of ion channels).  Pre-myelinated fibers, in at least
>>>>>some cases, are just as competent to have excitable membranes.

> This is true. The question is, just how "tuned" are our thought processes?
> How much do they depend upon internal synchronization? I don't believe
> that the answer to that is known. Certainly processes exist in less
> complex systems which do require a great degree of synchronization:
> take, for example, the escape reflex of a squid. How comparable that
> is to human thought, I couldn't tell you.

You must not be a behaviorist.

>>>> Premylinated fibers do conduct some impulses, certainly. They are, as
>>>> you pointed out, conducted at a much slower rate. They are also (if I
>>>> remember my neuro) subject to transmission failure at a fairly high
>>>> rate. 
>>>> As an analogy, consider the conversation we are having. If every third
>>>> line were dropped, or if random words were deleted, it would no longer
>>>> bear any resemblance to rationality.
>>>> How could we have rational thought with the same random loss of
>>>> impulses?

>>>I suppose if we built in enough redundancy, we might be able to pull
>>>it off.

>>Redundancy does not help if the signal is *lost*, although it would
>>help if *multiple* signals were being sent, and only *some* were being
>>lost. Does your study or neurology indicate tha tthe brain sends out
>>multiple copies of each signal? I admit I don't know one way or the
>>other.

> Pardon me for butting in here, but I have a small amount of relevant 
> experience, and this is a fascinating conversation.

Oh, you're more than welcome.  In my response to Mark's post, I
thrashed about as best I could to make the point you make so
effortlessly below.  I wish I'd known you were coming; I might
have been able to hide my ignorance a little longer :-)...

> Redundancy in the brain is not the same as redundancy in a computer,
> or even in most human engineered systems. Whereas humans tend to build
> redundancy in by having multiple copies or backups, the brain's 
> reduncancy comes about as a result of its distributed nature. A great
> deal of signal error or loss can be endured before the output, such as 
> it is, is significantly affected. Losing signal might be equivalent to
> say, losing a pixel from each letter in this post. 

> [deletions]

>>Further, we know that in early pregnancy, these same
>>roots must be myelinated before movement (other then twitches, which
>>occur as much from random excitability of the muscle tissue as
>>anything) takes  place i nthe fetus. Considering this, and considering
>>how much more complex the electrical activity of thought must be, do
>>you not think it is resonable to say that thought is unlikely to be
>>present?

> I consider that a reasonable assumption.

Reasonable enough to guide your own moral decisions?

> [deletions]

>>>Can you prove that consciousness exists?

>>To my own satisfaction, yes. But if "personhood" is based almost
>>wholey on subjective data and personal philosophy, isn't
>>"conciousness" as well?
>>If we define conciousness as the ability to respond intentionally to
>>oputside stimulation, then I think we can show it's existance. The
>>"intentionally" qualifier rules out the reflex motions o a fetus is
>>capable of, but also puts neonates on shakey ground.

> So? I don't see why any definition of personhood based on consciousness
> necessarily includes neonates. If evidence points away from it, why bend
> over backwards to fit them in? Science is really no basis for morals, and
> often makes a poor basis for laws. (Except when "ye canna change the laws
> of physics, Captain.")

Well, to me the issue is whether a given definition of personhood
is useful and/or widely accepted, and whether it leads to unacceptable
consequences.  Exclusion of neonates is, to me, an unacceptable
consequence, and IMO renders the definition useless.  If a certain
definition of personhood based on a certain definition of consciousness
resulted in the approximate onset of personhood being estimated to 
be age 8, I think most people would reject the definition as being
at least useless, if not downright scary.

I have argued, as you have, that science itself does not form the
basis for moral judgments or philosophical definitions, but provides
information for the application of those judgments or definitions.

>>>On a different tack, if I show that the developing brain of a
>>>6-week-old fetus is busily firing impulses (long before "brainwaves"
>>>can be detected by an EEG), then I can make a case for the
>>>POSSIBILITY of mental function.  Of course, I can't prove it
>>>exists, but this makes the situation quite different than, say,
>>>the contention that Elvis is alive on Mars.

>>Of course he's not, or I couldn't speak for his ghost. ;-)
>>The mass of tissue in a 6 week embryo (not fetus, not until week 9, as
>>you pointed out to another poster... ) which may eventually become a
>>brain may well be firing impulses. But does it qualify as "mental
>>function" (which I take to mean some relation (cousin, perhaps) to
>>intelligence)? Motor neurons fire at random, even in adults (you've
>>seen peopel twitch), so it can be assumed (or proven, possibly) that
>>others do as well. But for it to qualify as some omen of developing
>>intelligence, it would need to be (to me anyway) organized. 
>>I don't put much faith in the EEG, honestly. I've a friend in the
>>neurophysiology area who has been known to say "I can get an EEG of 3
>>cells in a petri dish." It's a far cry from the brainwaves seen in
>>adults, or even neonates, but it is an EEG...

> Here's where it gets interesting. I recently saw a paper which was an
> analysis of the activity in a fetal cat's geniculo-striate pathway and
> the lateral geniculate nucleus. What was assumed to be random activity
> now seems not to be, but rather a hard-coded sort of "training exercise."
> Even when the cat's eyes are closed (and in fact, have not ever been
> opened) this training is preparing the visual system for eventual use.

Whatever the data were, I suspect the above could be little more than
speculation.  Important developmental events such as synapse formation,
synapse elimination and cell death are frequently activity-dependent.
The presence of non-random activity in the developing brain is, IMO,
extremely noteworthy.  However, to conclude that it is a "training
exercise" is, I believe, a particularly risky bit of teleology.
Another plausible hypothesis is that the patterned activity is provided
for the specific sculpting of the geniculocortical connections via
activity-dependent processes (e.g. Hebbian interactions).

> Which raises the question: is the activity in a fetus' brain, which 
> might be mistaken for random thought processes, actually a training
> exercise for eventual thought and consciousness? If so, when does it
> cease to be training? I would tend to lean towards the point at which
> external stimuli begin affecting the patterns. 

Which could easily occur very early in neural development.

> Unfortunately, I don't have the references for the paper here, and
> I did not read it thoroughly when I had it. I'll dig it out tonight
> and see what it says. It's entirely possible that I read too much
> into their conclusions.

Please provide the reference if possible.  Sounds fascinating.

[deletions]

>>I can agree with you on the different realities idea.
>>We both see pre-birth "personhood" as a possiblity. I think the main
>>point of difference we have is that you choose to make any error (wrt
>>this possibility) in favor of the fetus (subject to the balancing you
>>mention above), while I prefer to make that possible error on the side
>>of the woman carrying the fetus.

> As I said above, I don't believe that science is necessarily a perfect
> guide to morality or legislation. If it can be incontrovertibly shown
> that "personhood" does not begin until some specific point, the conflict
> will remain. Just look at the number of people who will argue with all
> of their convictions that abortion is wrong, from fertilization onward.
> Personhood is an interesting philosophical and scientific inquiry, but
> I don't believe that it can lead to a resolution of the abortion debate.

Some, like myself, would be happy if the fetus' personhood were given
what we consider to be a fair shake.  If "the conflict" mentioned above
is the potential conflict between the well-being of mother vs. fetus,
then I agree that the conflict will remain.  I am skeptical that
there is sufficient conflict between mother and fetus to warrant the
discarding of the fetus and her/his personhood (whatever it amounts to)
1.5 million times a year.

>>>> BTW Steve, you forgot to include a gratuitous insult... Are you
>>>> slipping up? ;)

>>>Slipping up?  No.  Cracking up?  Why yes, you pathetic pile
>>>of primordial soup.  Was that gratuitous?  I'd better look it
>>>up...

>>HA! You admit you don't have the dictionary memorized? What sort of
>>t.a poster are you? Did your last EEG get reverse polarization and fry
>>that miserable excuse for a brain of yours??

> Can somebody please insult me? Nobody ever insults me... Do I have to
> insult someone else first? (Actually, I think I insulted Chaney or Hall
> sometime back, but I didn't get anything back. Oh, and I got Nyikos
> to post his SAT scores, but he forgot who I was. He did call me a "bozo",
> but that hardly counts. He didn't even use my name.)

Well, Mark's a recognized expert in the field, but I'd be happy to give
you my best shot, you hopelessly clueless, wishy-washy, hand-waving,
synapseless, overmyelinated, randomly distributed network nerd.
Whew.  Now I need a rest.

> John
> 
> p.s. I don't have a whole lot of experience in neuroscience. My background is
> from that hazy field of "cognitive neuroscience," which means I get to wave
> my hands around a lot.

--

Steve Matheson   Program in Neuroscience   University of Arizona
sfm@neurobio.arizona.edu