🚀 go-pugleaf

Robert wrote:
> "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).

> 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."

   Interesting stuff. This kind of remapping ought to be possible 
farther down the neurological chain, and here's a real-world example; a 
friend of mine was in a car accident that left him a quadriplegic as 
most of his spinal cord was severed, though some of his autonomic nerves 
were intact. He was told he'd spend the rest of his (short) life 
expectancy in a wheelchair. However this friend of mine does not have 
"quit", "can't" or "never" in his vocabulary, and a year later he was 
walking with canes, driving his car, and _flying a plane_ with hand 
controls. His neurologists were stumped because their tests showed that 
his voluntary nerves were not carrying signals to his arm and leg 
muscles. Their best guess was that somehow he'd managed to "piggyback" 
voluntary signals onto the autonomic nerves, though they can't do the 
kind of signal tracing needed to prove it. He has limited stereognosis 
and can feel pain and pressure but not heat or cold in his extremities 
(so far).

   He has no bladder control but can control his anal sphincter, and is 
looking forward to regaining erectile function despite his neurologists' 
saying "never".

   Only goes to show that sometimes, if you want a thing bad enough you 
_can_ have it.


   Mark L. Fergerson