From: L' Ermit (lhermit@hotmail.com)
Date: Tue Feb 26 2002 - 17:13:35 MST
Jake] Hmmmm... This is a first for me. I have discussed this before many
times in different crowds with lots of people foaming at the mouth on both
sides and no one has brought this up to me before. And now you AND Hermit.
Well, much as I respect you both, my default on this has to stay at roughly
---> other mammals have essentially the same nervous system as humans do
except for humans having greater cerebral capacity, and even that still
analogs the rest of mammalian brains except for relative size, therefore I
would tend to believe that they experience basic physiological things like
physical pain in similar ways to us<--- So, yes, I DO want to see something
on this "numbness" that you claim blesses our bovine cousins. And somehow I
think that if it is out there, you guys will find it for me. It's not
really a "like it or not" thing for me either. I am genuinely curious. Is
it just bovines, or do all other mammals! save humans share in this
blessing?? Hmmmmmm, if so, this human thing sucks worse than I thought.
[Hermit] It has been discussed here before. Perhaps in 1998 or 99.
[Hermit] As you observe, the human chordate central nervous system has a
large cerebral hemisphere and a brain stem connected to a spinal cord.
Nociceptive (detection of injury) stimuli causes an immediate protective
reaction called a reflex mediated by the spine and brain stem, but at that
stage, pain has not been felt by the person. The nociceptive activity is
transmitted to the brain stem where additional protective reactions take
place (avoidance responses, verbalizations). The nociceptive activity is
transmitted from the brain stem to various parts of the cerebral hemispheres
where it activates conscious awareness of the pain stimulus and generates
the emotional unpleasantness of pain. All mammals have enlarged cerebral
hemispheres that are mainly an outer layer of neocortex. In humans, this
neocortex is massively developed and this is the key to our ability to
experience pain.
[Hermit] If we beat up an animal without a recognizable brain, e.g. a
starfish, it will recognize injury through nociception, and will attempt to
move away from it (nocivoidance). Does that mean it is feeling pain? Most
researchers would argue that the lack of a brain precludes any sensation of
pain. It is simply a nervous reaction. Moving up the phylae, fish, have a
spinal column (chordata) and a functional brain stem, and, as the referenced
study shows [infra], shares a great deal of neural functionality and
response with humans. Yet trauma that would incapacitate a human has less
effect on a fish than simple fear, caused by applied restraints. If the
cerebral hemispheres of a human are destroyed, a comatose vegetative state
results. If the cerebral hemispheres of a fish are destroyed, the fish's
behavior is normal in most ways. I would argue, that a fish, lacking the
cerebral regions necessary for conscious awareness also lacks the ability to
and for generation of pain experience.
[Hermit] Looking more closely as humans as a model for animal reaction to
pain, when a person's thumb is hit with a hammer, the initial reaction
trigger is the local nervous tissue detecting the trauma (nociception). The
hand is jerked back due to activity in the spinal column (nocivoidance) long
before the signal reaches the brain. Next the signal reaches the brain stem
which triggers a boost in adrenaline, respiratory and cardiac activity. Only
after this do you have the opportunity to perceive that you are experiencing
pain. What follows involves suffering, but not necessarily "pain" unless
there is ongoing triggering due to an increase in internal local tissue
pressure (due to reduced drainage, infection or tissue damage) causing
ongoing nerve stimulation and brain stem reaction. The suffering we perceive
is not connected to the physiological perception of pain but is mediated by
the brain stem. We can see this more clearly when suffering occurs not as a
result of physical neurostimulation, but because of perceiving the death or
suffering of someone you love. Clearly in this case, there is no perceptual
effect involved, but that does not prevent it from resulting in suffering
and pain. Various in vivo tests (fMRI) have proved that the pain experienced
due to nociception is mediated by the brain stem, that the initial reaction
is driven by the spinal column, and that secondary responses are dependent
on cortic function. An even more convincing example occurs in stroke victims
who suffer from central pain, where pain is experienced (and is very
difficult to alleviate except through the use of luminal hypnotics which
allows it to be ignored), in the absence of injury due to damage to the
brain stem triggering cortical emotional responses, and where this can be
clearly seen using fMRI.
[Hermit] Modern analysis, particularly of quantifiable issues such as
measurements of such parameters as cardiac and respiratory responses, pain
scores, computer simulation and particularly the concentration of a stress
hormone in feces and urates shows that most animals, like humans, do
experience "pain" in the sense of detecting injury to themselves (this is
generally evaluated using a rough "discomfort scale" viz
[url=http://www.ahsc.arizona.edu/uac/iacuc/pain.shtml]The University of
Arizona Institutional Animal Care and Use Committee Handbook[/url]). But are
the physiological reactions "pain reactions" or something else? I would
strongly suggest that it is "something else".
[Hermit] fMRI studies show that the unpleasant part of pain in humans is
generated by specific regions of the frontal lobes of the cerebral
hemispheres. So we see that in humans, pain involves perception
(neurological nociception) and a consequent physiological (stress) response
as well as an emotional response and that it is the emotional response which
causes the perception of pain. Other mammals have radically different sized
frontal lobes and none have the specific cortical complexities where the
pain response is concentrated in humans. Cows and pigs' perception of pain
cannot possibly be anything like ours, due to their not possessing these
receptor sites and thus the psychological pain reaction component is absent
from their response even though the brain stem reactions to pain stimuli are
similar. In other words, the pain that humans experience is a psychological
experience and should be separated from the behavioral and physiological
reactions to injurious stimuli which we share with our less cortically
endowed fellow animals.
[Hermit] The above explains how an animal can remain functional - and indeed
happy - with a disease or injury where a human would be experiencing severe
shock. Unless a trigger is actively present, the animal is not perceiving
"pain", and while it will react at a brain stem level to minimize the pain
triggers experienced this does not imply significant discomfort. So a cat,
with half its face eaten away by a cancer will still purr and behave
perfectly normally, and it is often the owners sympathetic reaction which
leads to the euthanasia of otherwise functional animals.
[Hermit] It is perhaps appropriate to note that behavioral and physiological
reactions cannot be separated from fear - and indeed, most supposed complex
animal pain reactions have been shown to be fear reactions. As an example,
it has been shown that fish can experience both pain and fear (and it is
fear which appears to cause more serious distress in angling situations).
viz [url=http://pisces.enviroweb.org/carpfear.html]DO PAIN AND FEAR MAKE A
HOOKED CARP IN PLAY SUFFER?, Prof.dr.F.J. Verheijen & Dr.R.J.A.
Buwalda.Published April 1988.[/url]. Although it is possibly relevant that
for various reasons, Dutch and English researchers are recognized to have a
greater empathy for animals than US researchers (For more on this refer the
references below).
[Hermit] Having said that, animals do experience fear, and I would argue
that this is the aspect of abattoir practice which most deserves attention.
Visiting a high density abattoir shows animals in extreme states of terror
caused by the necessary restrictions on movement, and the experience of
frightening unfamiliar and unexpected sounds (and possibly smells) which I
have never had to deal with in animals being slaughtered in farm butcheries.
I would argue that we simply do not do sufficient to suppress the fear
reaction in mass slaughter animals and would personally suggest the use of a
rapid breakdown hypnotic drug delivered by injection, somewhere in the
process of moving them to the slaughter point, to prevent fear reactions
while not contaminating the meat. We do this for criminals before executing
them, we should do it for animals if we can avoid contaminating the meat
products.
Kind Regards
Hermit
Refer interesting discussion at
[url=http://www.spiked-online.com/Articles/00000000550C.htm]"Animal
research: a scientist's defense",Stuart Derbyshire[/url]
[quote]
It is a necessary fact that animals will die and suffer in the pursuit of
human betterment. By all estimates, at least one million monkeys died in the
race to halt polio. By the early 1960s, when vaccine production was running
smoothly, a previously dreaded disease that crippled or killed 20,000 people
a year in the USA alone was afflicting a few people per year.
Cases of polio became so unusual that an occurrence anywhere was startling.
It is a sobering thought that such an effort would, in all likelihood, be
impossible today.
...
It makes no sense for animal researchers to engage in a discussion of animal
welfare beyond ensuring that the animals will be properly housed, fed and
exercised, and that they will be generally physically and behaviorally
nourished as much as possible to benefit their performance as an
experimental subject. The idea that we should - or even can - be any more
concerned about their welfare stretches credibility.
Giving animals AIDS and other diseases, carrying out experimental surgeries
and infusing untested drugs hardly sound like procedures aimed at protecting
the animals' welfare. Mistreating animals is unacceptable because it ruins
experiments - but any further concern for the animals' wellbeing is beside
the point.
[/quote]
I would argue that the same goes for food.
Another is [url=http://www.spiked-online.com/Printable/0000000054FF.htm]"A
timeline of reaction",Stuart Derbyshire[/url]
Counterpoint is the question of whether animals feel empathy. The answer
seems to be yes.
Refer, e.g. [url=http://chronicle.com/free/v48/i09/09b00701.htm]Do Humans
Alone 'Feel Your Pain'?, FRANS B.M. de WAAL[/url]
and [url=http://www.sciam.com/1998/1198intelligence/1198gallup.html]Can
Animals Empathize? Yes[/url]
And I argue that this is another answer why suppression of the fear reaction
should be considered as a humane issue in slaughter animals.
_________________________________________________________________
Send and receive Hotmail on your mobile device: http://mobile.msn.com
This archive was generated by hypermail 2.1.5 : Wed Sep 25 2002 - 13:28:44 MDT