🚀 go-pugleaf

"Mark Fergerson" <nunya@biz.ness> wrote in message
news:5Wgof.30878$Mi5.10450@dukeread07...
> Randy Poe wrote:
> > Guy Fawkes wrote:
> >
> >>I have a mate who suffered a brachial plexus lesion after an accident,
> >>and when the arm withered went for voluntary amputation.
> >>
> >>the amputation saved the hassle of the awkward bit of "baggage"
> >>attached to his right shoulder and always getting in the way.
> >>
> >>the amputation made no difference whatsoever to the pain, which is
> >>considerable.
> >>
> >>his SO is a senior medical person here (UK) so he always had the best
> >>treatments and cutting edge stuff, just last year or so "they" (meaning
> >>doctors and consultants) accepted, as a result of completely new tests,
> >>that the pain he was feeling was in fact "real" pain and not "phantom"
> >>pain, as pretty much 99.999% of doctors prior to these tests
> >>insisted... "it's all in your head"
>
> > I thought "phantom pain" was real -- actual signals being sent
> > along actual nerves which no longer end where they used to.
>
>    It's "real" in that it's perceived the same way "real" pain is,
> because the relevant signals make their way to the brain. They're
> "phantom" in that the usual beginning of the path (pain receptor end
> organs) aren't there to begin the sequence any more, but were there
> long enough to get things started.
>
>    The plexi and ganglia between the end organs and the brain do a
> very complex summing of incoming signals, and one neuron somewhere
> along the way will so to speak enable or disable another neuron's
> activity depending on a lot of things, and if the "disable" signal
> doesn't come along (because the end organs are gone), the pain
> continues.
>
> > The signals just don't originate where the brain is interpreting
> > them as originating. But the signals are really there, nevertheless.
>
>    Yep.
>
> > Sort of like injecting a packet into a network with a fake
> > originating IP address.
>
>    Nope, more like a return ping isn't possible but the router(s)
> can't tell. Analogies are dangerous.
>
> > I never heard phantom pain called psychosomatic.
>
>    It was common before neurologists developed more realistic models
> (as opposed to the simplistic analogical models they had been using).
>
>
>    Mark L. Fergerson
>

There can be remapping of nerve cells as they can make new connections. A
lost arm can remap to the face for example. Stroking the face would have the
same effect as stroking the arm that is no longer there.
There is a way to trick the body and mind in some pain relief of phantom
organs. Psychiatrists have used mirrors in tricking your mind into thinking
one arm is the other and contracting and releasing tension pain.

"V.S. RAMACHANDRAN: The reason we think it happens is that in the brain
there is a complete map of the surface of the body. The entire left side of
my body, the skin surface, is mapped on to the right side of my brain along
a vertical strip of cortex which we call the "somatosensory cortex."
Similarly the right side of my body is represented on the left side of my
brain. So every point on your body surface has a corresponding point on this
body map. Now, it turns out that the representation of the face on this map
is right next to the representation of the hand. Now, that's a bit
surprising, as you'd expect the map to be continuous and faithfully
represent the left side of my body. But it doesn't. Now imagine what would
happen if the left arm were amputated. The part of the brain corresponding
to the hand no longer gets any input, and it's hungry for new sensory input,
so to speak. The sensory signals from the face normally activate only the
face area that's right next to the hand area. But they now invade the
vacated territory corresponding to the missing hand and start activating the
hand region of the brain.

And so, whatever is reading those signals higher up misinterprets those
signals. It says those signals are coming from the missing hand. So you
experience the sensations as coming from the missing fingers even though I'm
touching your face. This is showing there's been a massive reorganization of
the sensory pathways in your brain after the amputation. And it's as though
there's been a cross-wiring in your brain."

http://www.pbs.org/wgbh/nova/transcripts/2812mind.html