IUBio

Pain

John johnhkm at netsprintXXXX.net.au
Thu May 13 07:05:48 EST 1999


3/05/99 13:25

Jean Didier Vincent, The Biology of Emotions.
171
"We cannot follow the biological track and pass from physical to moral pain
without uttering cretinous generalities."

Here's some ... .


At the link below I read some interesting material regarding pain experience
in humans. (This draft paper is mostly about philosophical arguments re the
ontology of pain, it took some reading to find something neurological.)  It
seems that some patients who have a frontal lobotomy report a differing pain
sensation. The intensity, the "hurtfulness" of the sensation appears to
largely subside, even though the perceptual acuity remains apparently fully
intact. Patients with this operation report differing types of pain
(throbbing, stabbing, etc,) but more as a sensation than as a distressful
experience. Similiar to other senses perhaps, although I feel there must be
some distinguishing factor here; if only because we do tend to view pain as
something apart from the other senses. How about, pain signals the danger
has already arrived, the other senses are supposed to prevent this?

The primary perceptual experience of pain undergoes a substantial affective
change through the agency of the frontal lobes. It reminded me of something
I read years ago, Ornstein I think, where some paraplegics would report that
while feeling very angry they did not have the accompanying 'visceral'
responses and this changed the nature of their anger. No adrenalin I
suppose. Affect then may be the effect of the whole of neural activity, not
just some specific brain regions.

I do not think that the above experience of pain is confined to such
patients. In some circumstances it is possible for some people to not be
overly bothered by intense pain and push on regardless, probably arising
from a highly motivated state (frontal again) causing some strong inhibition
of distracting cues.

Is it perhaps an evolutionary accident that the frontal lobes are even
involved in pain 'management'? Perhaps evolutionary immaturity, our fresh
young frontal lobes haven't had enough time to deal with all this 'emotional
stuff' that forms the foundations of our lives. So many suicides, so much
emotional pain (which is often crying over spilt milk), rising depression. I
have read of studies showing that people from differing cultures can have
differing responses to painful incidents and events, it appears that how we
deal with pain at the personal level is not entirely fixed and probably, at
a young age anyway, there does exist considerable malleability in this
regard. What is it that the frontal lobes 'do' to this sensory information
that makes it so distinctive from other sensory information and give it such
urgency? After all, other senses can warn us of danger but do not create
such internal distress in the process. Can other senses overwhelm us in like
fashion(no evolutionary logic here)?

To get off the planet, what of a possible association between the frontal
lobes inability to correctly interpret or deal with pain and sociopathology?
Is there any evidence suggesting that sociopaths have a differing pain
mechanism? Do they as a rule have higher pain tolerance? Are they fascinated
by pain because they do not experience and understand it the way most do?

From:
http://cogprints.soton.ac.uk/archives/phil/papers/199807/199807018/doc.html/
pain.html

Draft paper by Murat Aydede, "Naturalism, Qualia, and Pain"


How can this theory [Gate Control Theory] explain reactive disassociation?
Even on the basis of this rough and ready picture, it seems clear that, in
reactive disassociation, the motivational-affective system somehow is not
working properly -- it is impeded -- while the activity in the perceptual
system remains intact. So although the incoming signals from the periphery
are processed and properly registered as pain in the perceptual system, they
either do not reach the motivational system or they do not produce their
normal effects to activate it in the appropriate way. Indeed, during the
1970's as the effects of many different addictive drugs on brain structures
were discovered, it became clear that most opium derivatives have direct
effects on different structures of the limbic system and the midbrain with
little or no effects on the cortex.[23] A bit later, it was also discovered
that the brain has its own opium-like substances (endorphins) and they are
found mostly in the same structures (as well as in SG).

The case of lobotomy seems to be a little different: the operation is not
performed directly on the limbic system, though there are other operations
close to the limbic system; instead, by cutting the connections between the
limbic structures and the frontal lobes, the limbic system is deprived of a
very rich source of input from the lobes. With the discovery of the unique
role of the limbic system in emotional experiences, it has become possible
to explain why seriously depressive patients do not care about their
physical pains, if they happen to experience any. Similarly, in some cases
of congenital insensitivity to pain, there is strong evidence that there is
something wrong in the limbic systems of the patients.

We need to delineate clearly what is suggested at the personal level by the
account that the gate control theory gives for reactive disassociation, and
make some consequences explicit. The literal interpretation of what is
reported at the personal level by patients in disassociation cases, combined
with its explanation at the subpersonal level by the best scientific theory
of pain we have got so far, strongly suggests what I have said earlier;
namely, that the inner phenomenology of pain experiences is, contrary to
what has been traditionally thought by the folk and even by some
philosophers alike, a highly complex matter, that we can distinguish at
least two qualitative components of this complex phenomenology. What makes
pain experiences hurt phenomenologically, that is, what makes them
"disliked," is the working of the motivational system. When, in the presence
of noxious stimuli, it is deactivated by certain drugs or when it is
isolated surgically from the perceptual or other higher systems as in the
case of successful frontal lobotomy, the awful or hurtful qualitative aspect
of pain seems to disappear. This is after all what is reported by the
morphine patients or by people who have undergone frontal lobotomy. These
patients, however, often insist that what they feel is pain and that it is
there as intensely as ever. This suggests that the inner identification and
individuation of what is felt as pain and the perception of its intensity
are components of the complex phenomenology of pain that should be kept
distinct from the awful, hurting, or "disliked" character of pain (which
seems to be what makes pains morally relevant). The inner identification of
pain and the registration of its intensity seem to be the job of the
perceptual system. As in the case of other sensory modalities, the site of
sensory processing of the noxious stimuli is in the cerebral cortex, namely
in the area called somatosensory cortex. (Indeed, morphine and lobotomy
patients seem to have no difficulty detecting and conceptually
distinguishing between shooting and throbbing pains, between burning and
pricking pains, and so on.)



John
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