Terri Schiavo Question

r norman rsn_ at _comcast.net
Sun Mar 27 11:23:35 EST 2005


On Sat, 26 Mar 2005 23:41:45 -0500, Carey Gregory
<tiredofspam123 at comcast.net> wrote:

>Steven O. <null at null.com> wrote:
>
>>First of all, according to the best available public evidence, is
>>Terri Schiavo's cerebral cortex completely, totally liquified, or has
>>there instead been a major loss of cortical tissue but with some
>>tissue remaining.
>
>Not totally, but a significant portion is gone now and replaced with CSF.
>
>>Second -- would it be possible for oxygen deprivation to cause loss of
>>the cerebral cortext, but for the lower brain centers to remain more
>>or less intact?  That is, can the cerebellum, limbic system, and
>>mid-brain remain pretty much functional and alive?
>
>Yes.
>
>>And, if yes, is there any evidence as to how much of Terri Schiavo's
>>lower brain centers remain active?
>
>She breathes and regulates blood pressure and pulse, so her lower brain is
>clearly functioning.  
>
>>Finally -- and here is the real kicker -- if the cerebral cortex is
>>gone, but the other brain centers remain alive, is there any
>>possibility that some kind of primitive experience continues, even
>>with all cortical-based thinking gone?
>
>Well, no way to know with certainty, of course, but ask someone who's been
>under anesthesia if they had a primitive experience.  Even before amnesia
>agents, the answer would have been no.  So even if they did experience
>something primitive, it appears to be irrelevant to life as we know it.
>
>>My understanding is that some lower animals have no cortical brain at
>>all, yet one would assume they still have some kind of experience or
>>awareness.  So, I am wondering if that could be the case for TS.
>
>She is responsive to physical stimuli, but so is an earthworm.  Does an
>earthworm know it is an earthworm?  Does it have thoughts and cares and
>desires?  Well, I don't think so, but that's un-provable.  What I do know is
>we would question the value of heroic surgical methods for keeping one
>alive.

Perhaps a better analogy would be a brain-pithed frog (or other
decerebrate animal preparation). You can completely destroy the brain
of a vertebrate, leaving the spinal cord intact, and produce clear,
seemingly "purposeful" reflex responses.  That is, tickle the
brain-pithed frog's belly and it scratches its belly.  Tickle its back
and it scratches its back.  It "knows" where the stimulus is located
and directs it response appropriately.  Of course, there is no such
"knowledge", only automatic activity.  People with spinal injury have
no knowledge or feeling or consciousness of what happens below the
injury point even though their bodies down there can respond.

Terri Schiavo has a lot more lower CNS function remaining than just
the spinal level, but the fact that there does exist a very low level
of CNS function does not automatically mean that the "person" is still
conscious or aware or perceptive or, if you will, "alive".





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