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Thread: Wise - Another Question!

  1. #1

    Wise - Another Question!

    Wise, what is your opinion of the evolutionary reason for the over-wiring of the spinal cord? I mean, if 10% of the white matter survives a person can function as if not injured so 90% is apparantly not needed
    Maybe the other 90% is spare so that in case tissue death by injury or old age there is plenty to take over
    Maybe the other 90% is a multiple reproduction of the necessary 10% and the more feedback there is the smoother and more natural the movements are

    Wise, what do you think?
    It kind of concerned me reading of walking quads who after 30 years lost there ability to walk - did there small surviving fibres just die out and there is no back up fibres to take over - in which case, a "cure" might not last a life time.

    Thanks

    Chris

  2. #2

    Redundancy or Plasticity

    The fact that 10% of the spinal cord is necessary and sufficient to support substantial functional recovery suggests redundancy of spinal tracts. But it may also reflect the remarkable plasticity of the brain and spinal cord. Many studies have now suggested that the brain and spinal cord are capable of adapting to tremendous losses of circuitry and somehow utilize the remaining circuits to achieve function.

    In the 1980's, Swedish researchers systematically cut individual spinal tracts to determine their function. The animals lost function for several weeks but gradually recovered the function. Please note that the recovered function is not identical to normal in all cases. The animals sometimes used different strategies to achieve the same function.

    Note that there is not only redundancy of neural circuits but also redundancy of muscles. In many cases, multiple muscles subserve similar functions. This is true in both the hands and legs. If you damage one muscle, other muscles can support the same function.

    Both redundancy and plasticity are clearly very advantageous to survival. Animals that recover ability to recover rapidly after spinal cord injury are more likely to survive and pass their redundancy and plasticity genes to offsprings.

    Wise.

  3. #3
    So would you say this plasticity is in our favour in hoping for a cure? Absolute correct connection of axons is not necessary but you'd perhaps have to be careful not to injure the same spot again as no back up circuits would be available

  4. #4
    Senior Member alan's Avatar
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    Doesn't this also happen in strokes if they're not too severe?

    And here's a really radical situation - heminspherectomy (removing half of the brain.) Apparently, the few people who've needed it done eventually wind up not overly impaired - the remaining hemisphere takes over functions of the removed hemisphere (the Discovery Channel has some interesting programs.)

  5. #5
    Chris, plasticity is great but redundancy is even better. The more axons and the better the connection the better. I have had a sea change in my view of regeneration in the past two weeks, since I came back from Japan and saw Kawaguchi's material. He has convinced me that it is possible to regenerate the spinal cord at a level that I did not think was possible before. He is getting such good regeneration of the adult rat spinal cord that it is difficult to tell where he cut to transect the cord. So, I am setting my aims higher than before. Wise.

  6. #6

    read Wise's last post here!

    Wise

    that sounds fantastic!!!!!!!!!
    if it's not possible in a human injury to clean cut the spinal cord and bring the two ends together, we need to find a way of duplicating or mimicking the situation

  7. #7
    Senior Member mikek's Avatar
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    Wise tell us more.........

    Can you describe Kawguchi's regenerative therapy
    to get such fantastic results.

    Post SCI syndrome of losing functionality with
    age is a reality but the future holds so much
    promise !!!

    Mike

  8. #8
    Kawaguchi's method and skill seem truly fantastic but scare the hell out of me.

    Full transection? MAN! A blunt trauma is one thing. But slicing my cord completely in two and then reattaching the ends just....frightens me.

    My guess is, and please excuse my ignorance Dr. Y., that basically from what I've read and understand is that Kawaguchi essentially uses surgical instruments (knives) sharper than anything currently available or known to modern medicine. He transects (slices) the cord cleanly and completely through then reattahes the two ends. The cut, being as clean as it is, renders each section virtually identical, healthy and unencombered (no messy scar) therefore allowing for more complete axon regrowth / reconnection and therefore - regeneration.

    Do I have the concept right?

    Hey, if it works, my hats off but if it doesn't then what do you do?

    Onward and Upward!

  9. #9
    I don't think that it is Kawaguchi's procedure that is so revolutionary but rather what he considers to be the primary obstacles to regeneration. He rejects the concept that inhibitors of axonal growth, including Nogo and CSPG, are significant obstacles to axonal regeneration. He believes that the problem is due absence of an appropriate growth path at the injury site. His most recent work, soon to be published, but presented in meetings in Japan, suggests that it is the gap of glial cells at the injury site. Thus, his approach is to either create an injury that has no astrocytic gap or introduction of astrocytes so that there is a continuous path for axonal regeneration. He has also convinced me that regeneration can be more complete than I had thought possible, if the conditions at the injury site are appropriate. Wise.

  10. #10
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    Kawaguchi's method

    I may be way out in left field on this, but it almost seems to me like this method of an absolute cleanly transected spinal cord to provide a continuous path for axonal regeneration reminds me of fiber optics. From my very basic understanding of joining fiber optic network connections for optimal bandwidth, a crisp 90 degree 'transection' is a must to provide an uninhibited pathway for network packets to travel upon. So it almost sounds to me like Kawaguchi is using the same technique that somebody dealing with fiber optics would use - if the connection is bad, cut it again and resplice it to make a clean connection(say without scar tissue) so the data can get through. Only he is providing this clean path for axon regeneration. I wonder if there is anybody out there who is knowledgeable enough to know if fiber optics and spinal cords function at all in the same way?

    Just a thought,
    Chris

    BTW, exactly how many of us here have that name?

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