Follow Slashdot blog updates by subscribing to our blog RSS feed

 


Forgot your password?
Close
typodupeerror
×
News Science

Severed Optical Nerves Can Be Made To Grow Again 187

Posted by chrisd from the well-will-you-look-at-that dept.
Anonymous Coward writes: "It is being hailed as one of the most significant advances in nerve regeneration in a decade. After severing an optic nerve in rats, neurologists have found a way to reconnect it to the brain so that it once again transmits normal electrical signals. As reported in the New Scientist this achievement is a first in mammals, and may hint at ways of reversing some types of blindness in people. Scientists also hope to use a version of the technique to treat people with spinal cord injuries.
This discussion has been archived. No new comments can be posted.

Severed Optical Nerves Can Be Made To Grow Again More

Severed Optical Nerves Can Be Made To Grow Again

Comments Filter:

  • What about other nerves? (Score:3, Interesting)

    by Skyshadow ( 508 ) on Thursday December 06, 2001 @06:48PM (#2667834) Homepage
    It you can regenerate the optic nerve (or rather, prompt it to regenerate), what about other nerves? Spinal cord? Maybe you could make Rush Limbaugh hear again (or at least make him deaf only to the poor, human suffering and forward-thinking ideas like he was before).
    • Apparently they've been able to regenerate spinal cords in rats too. There's an article about it here. [about.com] Those rats are some resilient little buggers! (So there's hope for that rat Rush Limbaugh yet ;) )
    • Nerves are hard to regenerate once cut - the actual nerve cells only proliferate at birth, so if you lost a nerve cell that's them gone forever. (That's why there so much research into trying to get stem cells to differentiate in vitro - they can be used to replace these cells which cannot divide)

      However, if you cut the axon of the cell (the bit which connects to other cells put very simply) it can regrow, but don't expect it to take the same function. The part of the axon which is cut off will die, and the cell should make new synapses. As I said these might not be of the same function.

      The technique described could work for spinal axons, but there are a lot more of these than in the eye. So you would have to get each cell to connect to its exact axon in the first place and then stimulate them to reconnect. I would think it would be quite difficult to do the above.

      Anyway after this the patient would have to learn to regain control of their body. Note how they said it only partially regenerates the nerve. You're still not going to get all sensation or motor control - the potential for damage to a person who undergoes this and cannot control themselves properly is massive. I can't see this working for a time, and then there will have to be years of trials (after persuading ethics committees that this is a good ides). I think they'll have to find a way of improving the technique first.

      I have no clue who Rush Limbaugh is - is he metaphorically deaf? His deafness might not be due to damage to nervous tissue anyway, but could be due to damage to the actual ear.

      (Some of the above is IMHO, and some of the facts may be wrong - or oversimplified - as science moves very fast; try searching biomedical databases for yourself to see how hard it is. Correct me if i've got anything wrong please)
      • I have no clue who Rush Limbaugh is...

        Check it: http://rushlimbaugh.com [rushlimbaugh.com].

      • Nerves are hard to regenerate once cut - the actual nerve cells only proliferate at birth, so if you lost a nerve cell that's them gone forever.

        Actually, the formation of new nerve cells in the adult human brain has been observed for several years now. Your statement would have been taken as correct some years ago but is now known to be incorrect. As you noted yourself:

        science moves very fast

        Cheers,
        Tim
        • Actually, the formation of new nerve cells in the adult human brain has been observed for several years now. Your statement would have been taken as correct some years ago but is now known to be incorrect.

          Or perhaps not. [yahoo.com]
          . . . in a paper published in the December 7th issue of Science, Dr. David R. Kornack of the University of Rochester in New York and Dr. Pasko Rakic [amazon.com] of Yale University in New Haven, Connecticut, report that they did not detect the growth of new neurons in the neocortex of adult macaques. . . Based on the findings, the researchers conclude that "neocortical neurons are not normally renewed during the life-span of macaque monkeys." The same may be true for people, they state.

      • Re:What about other nerves? (Score:1, Informative)

        by Anonymous Coward
        As the article points out, nerve cells themselves are only too happy to regrow... the reason you don't observe this in the case of physical injury is that, in mammals, scar tissue actually inhibits this regrowth. So if we can convince areas to be uninhibited, it could be a huge breakthrough.
    • Rush Limbaugh hear again (or at least make him deaf only to the poor, human suffering and forward-thinking ideas like he was before).

      So smaller gov't and personal responsibility are not forward thinking?

  • does this mean (Score:1, Redundant)

    by Anonymous Coward
    that we can connect our brains to fiber optics and record our thoughts? or would that be illegal under the DMCA, since we might think of something copyrighted?
  • The complexity of this discovery compared to our current understanding of nerves can be likened to a comparision between a toaster and a computer.

    This is very awesome for those of us who are on our way to blind or know people who are.

  • whoa (Score:1)

    by vectus ( 193351 )
    This is awesome. I wonder about how this will affect the emerging feild of cybernetics. This seems like it would make it more possible to implant electronics into people's brains and other body parts.


    Imagine having a mathematics co-processor, that solved every mathematical equation almost instantly, directly embedded into your brain. Even if only a few people chose to adopt these, the advances they could make for physics and math are staggering.


    I know a lot of people would be uncomfortable with implanting technology into their bodies.. but, to me at least, the idea of a society in which information could be wirelessly transmitted in to your brain is beyond cool.


    (disregarding the potential for abuse, that is)

    • (disregarding the potential for abuse, that is)

      Like making your brain open source? ;-)

    • Actually, most of the problems of math and science could not be solved by a math coprocessor in a brain. It doesn't take that much time to move the problem from your head to a computer. The problem is not so much solving the problem as it is formulating it correctly. Like so many things, the correct representation of a problem often makes the solution trivial. So many things (like strong AI, for example, or the mind), just don't have good strong representations to work with.

      Of course they could go through those possible representations and rule out the bad ones more quickly. =)

  • VISOR eyes (Score:1, Funny)

    by Anonymous Coward
    I'd rather have those visor-eyes that Geordi gets in Star Trek 8, to be honest.

  • I Predict (Score:1, Offtopic)

    by XBL ( 305578 )
    that a Barbara Walters interview with Christopher Reeves will be coming up soon.
  • does that mean last night's "Kenny Dies" south park was actually right about something?

  • How long until human trials? (if ever) (Score:3, Interesting)

    by tuj ( 303347 ) on Thursday December 06, 2001 @06:55PM (#2667891) Homepage Journal
    A very good friend of mine has a rare problem with the optic nerves in his eyes, which causes his vision to be so blurred that he is legally blind. All tests indicate that his eyes are shaped perfectly; he should have 20/20 vision. Furthermore, the doctors haven't been able to do much for him, since they dont' fully understand the problem. So they try to give him eye-glasses, and magnifiers, which don't do much good.

    Research like this, when it might potentially spark a break-thru that could help someone close to you, is always great to see. I hope they make serious progress with this one.

  • Someday the tables will turn... (Score:5, Funny)

    by Rothfuss ( 47480 ) <chris,rothfuss&gmail,com> on Thursday December 06, 2001 @06:55PM (#2667895) Homepage

    The team is currently studying the rats' behaviour to assess how good their eyesight is.

    While the rat team is currently trying to figure out how to anaesthetize a large group of humans, and then gnaw their eyes out.

  • Interesting, semi-on-topic Oliver Sacks tidbit (Score:5, Interesting)

    by melquiades ( 314628 ) on Thursday December 06, 2001 @06:57PM (#2667901) Homepage
    I once heard Oliver Sacks talk about somebody who had been blind their whole life (due to completely opaque cataracts, I believe). A new surgery technique restored the fellow's sight. But when he woke up from surgery, all he could see was an overwhelming mass of incomprehensible color. He couldn't distinguish faces, object, or even simple shapes.

    His eyes, it turned out, were functioning perfectly. But because he has been blind during infancy, the visual parts of his brain had never developed -- he had never learned to see.

    He did slowly learn, but it was agonizing for him. His newfound sight was overwhelming and sent his brain into chaos. After a long time, with tremendous effort, he could shave for a minute or two in front of the mirror -- but it was absolutely exhausting, and had to finish with the lights off.

    Eventually, an unrelated optical infection threatened to take his sight, and he chose to let it run its course. Returning to blindness was a tremendous relief.

    Perhaps slightly off-topic, but fascinating!

    • That's pretty interesting. I wonder how someone like myself, who can only see out of one eye due to a birth defect, might react to being able to suddenly see out of both eyes.

      Maybe I would be able to play baseball. The only time I've ever hitten a baseball with a bat was on accident when it was coming towards my head and I ducked with the bat over my head.

      • Maybe your good eye's experience would "teach" the other one how to see quicker than a totally blind person could learn it.
      • If it's any consolation, I have two eyes but almost NO stereopsis (I have a condition where my eyes don't focus on the same spot, so I never learned to see in 3D). I had an inkling of this when we were told in science class to butter bread with one eye closed, and I noticed no difference in my perception or ability.

        And I can hit a baseball.

        My grandfather who has the same condition was almost a tennis pro.
        • I have the same (or similar condition) where I focus with one eye at a time. As a baby the doctor observed I wasn't using one eye at all and it became a "lazy" eye. So they corrected the muscle tissue with surgery, and brought them into near-perfect alignment. But I still faced the threat of going blind in one eye. So the doctor told my mother how to train me to switch dominant eyes regularly and work the muscles that allow me to focus. Thanks to that training I didn't even need glasses in school until junior high.
          Things like windshield wipers are a problem though... when they move to the left, my right eye becomes dominant, and vice versa. Imagine switching eyes 2000-3000 times an hour? Serious headache.
          But there's a point to this babbling...
          During a routine eye checkup last year for new glasses, I saw an optometrist I hadn't seen before. When I was unable to complete one of the tests he gave me that required both eyes in focus at the same time, he got testy while I explained the situation and kept trying to force the issue by adjusting the distance between lenses. Finally he blurted out that my doctor must have been an idiot and it would have been better that I go blind in one eye.
          Can you believe the ignorance of some of todays medical/optical practitioners?
          Even without "perfect" vision or "perfect" depth perception I could still have put a dart in his eye from across the room.
          Different isn't necessarily bad, and if any of you ever have children that possess what one doctor calls a handicap, look for other doctors who may find a way to change it to a minor setback.

    • Oliver Sacks rocks (Score:5, Informative)

      by Reality Master 101 ( 179095 ) <RealityMaster101@gmail. c o m> on Thursday December 06, 2001 @07:09PM (#2667981) Homepage Journal

      If anyone has any interest in how the brain works and the insights one can gain by looking at what happens when the brain malfunctions, I can't recommend the Oliver Sacks [amazon.com] books highly enough. He's a neurologist who studies the brain and has a positive gift for writing about his subjects. Not to be touchy-feely, but he writes about them in a very sensitive way to where you don't feel like people are getting "exploited" for his own gain.

      Other tales in his books to whet your appetite:

      1) "The man who mistook his wife for a hat", which is the title of one of his books about a man who, otherwise normal, had problems with misconnecting objects to their identities,

      2) A woman who could perceive things only on one side (say the left), but not on the other, even though her vision was perfect. When she ate, she would have to eat one side, then turn the plate, eat another half, etc. She was perfectly sane, but just had this wierd perceptual problem.

      3) The man who could not make new memories, and lived the same moments over and over. He could remember everything up to an accident he had, but nothing further. Every day he would re-meet the same people. They have to keep mirrors away from him because it freaks him out because he looks too old for himself.

      4) The "anthropologist" on mars, who is a pretty famous autistic teacher I think at Colorado. She has perfect image recall, but is entirely without emotions. She actually has her own book that she wrote about what it's like to be her, but I can't remember the name of it (anyone?).

      The books are absolutely chock-full of stories like this. If this stuff fascinates you like it does me, I give these books my absolute highest recommendation.

      • Re:Oliver Sacks rocks (Score:4, Informative)

        by Reality Master 101 ( 179095 ) <RealityMaster101@gmail. c o m> on Thursday December 06, 2001 @07:16PM (#2668024) Homepage Journal

        Here we go: The book about the autistic teacher is called Thinking in Pictures" [amazon.com] by Temple Grandin. I've read this book, too and it's incredibly fascinating. The title reminds me of how her brain works. She literally thinks in pictures, and has to "translate" the pictures into words through a methodical process that she had to learn by rote.

      • do you have the ISBN numbers for any of them?

        Ta. Mlk

      • Hmmm. Apparently my Amazon link was fubar. How about this one: Oliver Sacks [amazon.com].

      • The man who could not make new memories, and lived the same moments over and over.

        Reminds me of Memento [imdb.com]. Pretty cool flick, worth checking out.
      • In my PSYC111 class last year, the neuroscience lecturer read us that story (The man who mistook his wife for a hat). IIRC, he had associative agnosia - he could describe parts of something, but not tell what the thing was as a whole.. eg: he descibed a rose as "a convoluted red form with a linear green attachment" which personally, I think is a fantastic description. Then the doctor told him to smell it, and he identified it as a rose instantly.
        The brain is a pretty interesting thing.

        An even more interesting brain-related story is that of the split-brain syndrome (getting pretty OT here) where the bundle of nerves connecting the two hemispheres of the brain is split, which is sometimes done as treatment for severe epilepitics. Because all the language functions are in the left hemisphere of the brain, people who undergo this procedure often say that the left side of their body (controlled by the right hemisphere of the brain) seems to "have a mind of its own". It gets even weirder when people deny having noticed stimuli, when they have responded to them (confused? Read this [macalester.edu].

      • there was recently a movie about #3, (I think it had Carrie Ann-Moss in it) the scenes were in backwards-order from the sequence in which they occurred, giving the viewers the same sense of newness when another facet of the story was revealed. Of course, it was kind of a mystery-thriller.
        He's hunting for the murderer of his wife, and all along, the people around him are manipulating him to kill people for him, by convincing him that they're the killer. He wrote himself notes, and tatooed facts about the killing on his body so he could remember how to find the killer. Funny, and strange. I thought it was a good movie, but I can't for the life of me remember the title. Hey, who are you anyway, do I know you?
    • That is exactly the story portrayed in the movie "At first sight" [imdb.com] (iMDB link) starring Val Kilmer/Mira Sorvino. The guy got his sight as result of medical treatment and he couldn't live with it.
      • Oh, just found out, Oliver Sacks wrote script for this movie.
      • I'm no movie critic but I found that movie horrible. The blind angle was the best part of it, but that's not saying much. Kilmer came off as *incredibly* whiny and the chemistry was exceedingly forced and shallow. Especially the crying on the massage table bit. Little character growth. Almost as bad as "Meet Joe Black". (So if you liked that movie, go see this one.)

        I am *not* trying to belittle this condition, but if you want to know more about it instead of just watching the Beautiful People mumble their lines (..and that can be fun sometimes..) I would just pick up the book instead.

    • Yeah, I saw something like that in a Val Kilmer movie -- it's gotta be true!

      :)
    • I once heard Oliver Sacks talk about somebody who had been blind their whole life (due to completely opaque cataracts, I believe). A new surgery technique restored the fellow's sight. But when he woke up from surgery, all he could see was an overwhelming mass of incomprehensible color. He couldn't distinguish faces, object, or even simple shapes.

      His eyes, it turned out, were functioning perfectly. But because he has been blind during infancy, the visual parts of his brain had never developed -- he had never learned to see.

      The movie Out of Sight [mgm.com] is based on Sack's story [amazon.com]. I highly recommend watching the film.
    • Yes, and they made it into a movie: _At First Sight_, with added the typical Hollywood romance, of course.

  • I thought 'optic nerves' were actually brain cells (Score:2, Funny)

    by Anonymous Coward
    and not nerves at all. Either way, it would make a great message-passing backbone for a Beowulf cluster.

    --Patrick Bateman, Esq.

    • umm what exactly do you think "nerves" are made up of?
    • That's not neccesarily true... the processing power of the brian lies in its parallelism. Comparing switching speed of neurons to typical network bandwidth and thouroughput of a string of neurons to that of a typical network pipe embarrasses the biological contender.

      HOWEVER, on the note of parallelism, it a networking system could somehow be developed that was parallel in nature, this may lead somewhere. :)

    • Close...
      The oflactory nerve (aka Cranial Nerve I) is not a 'nerve' but rather a direct extention of the brain.

      I am fairly certian that the optic nerve (cranial nerve III) is, outside of the dura and therefore is a nerve.
      • Close...


        I am fairly certian that the optic nerve (cranial nerve III) is, outside of the dura and therefore is a nerve.

        Close again... The retina is probably most accurately described as part of the brain. A strong argument for this description comes from looking at how the eye develops embryologicaly. Also, there are four layers of neurons in the retina, just as there are four layers of neurons in areas of brain cortex which are phylogenicaly old. (hence the term neocortex for cerebral cortex, which has six layers of neurons and is a recent evolutionary design.) The cell bodies of the neurons making up the optic nerve are in layer four of the retina and synapse with neurons in the thalamus, another phylogenicaly old brain structure. So, it is "brain all the way down."

        So, should we call cranial nerve II (you wrote III, but you meant to say II) a "nerve?" or should we call it a "tract?"

        Glad you asked. The real distinction is between central nervous system and periphrial nervous system. PNS neurons tend to heal, while CNS nerves do not. It is believed that this has much to do with the differences among the cells which provide support for the CNS vs PNS. For example, the myelin in PNS is provided by schwan cells, while the myelin in the CNS is provided by oligodendricytes, and there are many other differences in the "support staff" between CNS and PNS.

        So, you ask, is CN II really a nerve or is it a tract? Well, if you look at it closely, it is realy part of the brain, and therfore properly called a tract, but the convention is to call it a nerve until it reaches the optic chiasma, then call it a nerve. But whatever you call it, it is very differant than the sort of nerve which gets cut when one, say, puts their hand through an old glass door.
  • This can also be applied to robotic prosthesis, and other nerve machine connections. This might allow the synapsis to grow into a mesh/matrix of nerve-electronic component connections.
  • The regenerated nerves also carried normal electrical signals, suggesting that they had rewired themselves into the brain, although the connections were a bit scrambled.
  • None are so blind as those who can not see;
    from the article:
    The regenerated nerves also carried normal electrical signals, suggesting that they had rewired themselves into the brain, although the connections were a bit scrambled.

    Does that mean we don't need DeCSS, once the MPAA requires, via a click thru agreement, no doubt, that we all be blinded before watching any of its movies?

    Seriously, this is great news, now we just need to be able to regenerate brain cells, that way corporate execs will have more than one.

    Oh, and find the "clue" gene...

    ;)

    moose

    .

  • Crystallins or Immune Sys? (Score:4, Interesting)

    by krmt ( 91422 ) <therefrmhere@yah o o . com> on Thursday December 06, 2001 @07:07PM (#2667971) Homepage
    I thought the idea that it was immune system stimulating growth pretty interesting. The immune system releases a lot of signaling molecules at all stages. I'm not an immunologist per se, but I've never heard of any of them stimulating growth, but that certainly doesn't rule out the idea.

    The article said that it was just inflammation that induced growth. I somehow doubt that, since everyone who's ever had irritated eyes has felt the fun of histamines and the primary immune response in action. If that sort of thing could make the blind see again, I'd be really surprised, even if it is on a larger scale.

    If it is the immune system, I'd bet on cytokines released by helper T cells (those things that HIV targets) simply because these cells release a ton of stimulants. This may be triggered by the nonspecific inflammation like the author suggested, but I'd bet on the helper T as actually secreting growth signal.

    If it is possible to use the immune system to regrow neurons, it's very likely applicable in other parts of the body too.

  • What if...? (Score:2, Insightful)

    by BigBir3d ( 454486 )
    Ok, they can get severed optic nerves back together, and working, that have been cut with a laser scalpel or some such thing. What if they are fixing naturally degraded optic nerves where there is not enough length (damn cat5 cable is just too short...) left? Is there a way of extending the nerves? Are we talking about splicing in "new" nerves that were "grown" in a lab or something else?

    Still a very cool development!
  • Consider the possibilities: With this we can now reconnect optic nerves. The important thing is that if you remember, way back some time ago (can't find link, oh well) a method of drawing images directly onto the retina (assuming the optic nerve was connected still...) was developed. This effectively means a cure for any eye problem.... not too shabby.
  • a breakthrough would be if I could hook up my brain directly to the video output on my computer.
  • ...everytime I hear something from New Scientist I can't help thinking about this article [theonion.com]. Its often interesting to read, but the results are not from an accountable source - always from some scientists somewhere that have questionable results...

    All of the big breakthroughs that are real seem to be reported by actual news institutions.

    Its just another straw on the coffin (another nail in the camel's back).

    • ...but the results are not from an accountable source...
      All of the big breakthroughs that are real seem to be reported by actual news institutions.

      or in academic journals [academicpress.com].

      Did you miss the citation at the bottom of the New Scientist article? or do you just believe that PR folks make the world go round? or something else?

  • fix the optic nerve by a good poke in the eye (Score:3, Funny)

    by binarybum ( 468664 ) on Thursday December 06, 2001 @07:33PM (#2668109) Homepage
    "Finally they punctured the lenses in the rats' eyes which releases proteins called crystallins."



    Well, we could repair your optic nerve miss, but it will involve crushing the lens of your eye. You'll be able to see again, but everything will look like it does in a circus mirror.

  • I debated until I was blue in the face in high school biology classes that nerve tissue can regenerate if given the right materials and circumstances. Unfortunately, they were too closed minded to realize that regrowing nerve tissue isn't really that hard.
    • I don't think regrowing nerve tissue is that hard (as long as the original cell body of the nerve is still intect). It's making the nerve grow so that it regains its previous function which is the hard part.
  • FINALY! I have been waiting for _YEARS_ for a breakthrough like this. Man shitty day so far, this makes is worthwhile and them some!!! YEEEES!!!!!!!

    I'm legaly blind in one eye, I have almost no depth preception. You know all of those 3d monitors that people keep on getting excited over? Well if Science keeps up its march I may be able to use them one day!! YAAAHHOOOOO!!!!

  • Not applicable to humans (Score:1, Informative)

    by Anonymous Coward
    The so-called "animal model," such as that used in the experiment described, has received increasing criticism in recent years. A number of scientists have gone so far as to state that animal research for human health is categorically invalid. There exist several physician groups which oppose all animal experiments, for reasons of scientific invalidity alone:

    • There exist several physician groups which oppose all animal experiments...
      ...and if you believe any of the bunk put out by those organizations (little more than fronts for the likes of PETA and ALF, really), I have a bridge in Brooklyn I'd like to sell you.
  • The story does not say anything about sight having been regained through use of the technique, only about the degree of regrowth. If any tests on sight were done, they are not mentioned. That makes this result highly questionable in terms of possible clinical value.

    There are many things that could thwart the restoration of sight -- for instance, if severed axons joined to the wrong partners, then sight could be kaleidoscoped; or if the axons grew back incorrectly, they might not transmit action potentials reliably.

    Given that the lens is damaged in this procedure, it might not have been possible for them to test sight, but assuming there are other possible sources of crystallins, a followup experiment that tests for sight restoration should be this team's first priority. I'll go out on a limb and predict that 30% regrowth plus probable kaleidoscoping will prove to be only barely useful.

    Tim
    • Actually, believe it or not, the brain should be able to sort this kind of thing out. I'm not saying immediately, but give it some time, particularly if the person had sight at some point previously in their life.


      There have already been studies done with people that wore lenses that inverted their vision. They were forced to wear these lenses for weeks at a time. After about a week, their vision righted itself -- they saw perfectly normal. Of course, when they removed the spectacles, they had to readjust again.


      Provided all the information is intact, I don't doubt that the brain could unscramble it. I would imagine when we were newborns we couldn't see too well either -- we just don't remember it.

  • I have to wonder... (Score:5, Interesting)

    by Alioth ( 221270 ) <no@spam> on Thursday December 06, 2001 @08:06PM (#2668268) Journal
    One thing I have to wonder about is if the nerves grow up the 'wrong' pathway, and how long it will take the brain to sort it out.

    When I was 15 years old, I put my hand through an old glass door while trying to open it. The glass sliced through my right wrist, severing pretty much everything (apart from about half of one tendon). I probably don't have to mention the large quantities of blood that went everywhere.

    Six hours of microsurgery, and it was put back together again...followed by three months of three hours a day physiotherapy.

    The thing I found fascinating was that when the median nerve [0] (the nerve that runs up the middle of your wrist and supplies your index finger to thumb and half your palm) is that some of the nerves went the wrong way. I could stroke part of one finger, and the sensation would come out somewhere else - like a different finger, or a different side of the finger. It was...well...very weird.

    However, it didn't take long for the brain to fix it. After a short while, the brain learned the error, and sensations came out in the expected place.

    It's one thing when this happens to fingers - but I wonder if you'd need some kind of "optotherapy" to coach the brain to fix the image problems you'd get with optical connections wired differently to how they were before.

    [0] Movement of the fingers is controlled by the muscles in the forearm. The median nerve does sensation.
    • However, it didn't take long for the brain to fix it. After a short while, the brain learned the error, and sensations came out in the expected place.

      so that means your brain released a kernel patch?
    • Yep. Brain can rewire, and it does it better the younger you are. Almost never gets it perfect, though. I'd bet money you never quite got back the same dexterity and sensitivity you had in your hand before your accident.

      My bigger point, though, is that you're not quite right about the median nerve. It does both sensation and motor. What happens is that as the nerve passes through the anterior compartment of the forearm (that'd be the side you see when your arm is facing up), it innervates those forearm muscles. The nerve then dives into the carpal tunnel (yep, this is the CTS nerve) and re-emerges in the palm. It has some motor branches here as well; the muscles at the base of your thumb get innervation from the median nerve. You're correct in that after it enters the carpal tunnel, it's mostly sensory.

      That concludes our semi-educational semi-tirade for the day.
      • Yep. Brain can rewire, and it does it better the younger you are. Almost never gets it perfect, though. I'd bet money you never quite got back the same dexterity and sensitivity you had in your hand before your accident.

        Dexterity-wise, I can't tell the difference. It was my right hand, and I still write with it, and it doesn't stop me from playing the piano. Nor playing Unreal Tourney :-]

        I can tell the difference in sensation still if I really try and notice, because I can compare with my left hand. I can't really notice a difference in sensitivity, it's just some sensations feel slightly different than they do with the left hand.

    • apparently, after wearing glasses that invert your vision (everything looks upside down), after about 12 hours your brain will correct the problem and everything will look the right way up again ... the brain is a pretty amazing thing. how long till machines can self-heal by completely changing their functionality like this?

  • Seen it happen... (Score:3, Interesting)

    by Xerithane ( 13482 ) <xerithane AT nerdfarm DOT org> on Thursday December 06, 2001 @08:16PM (#2668303) Homepage Journal
    My girlfriend introduced me to this guy, who everyone refers to as 'Jedi' at the local pool hall. He was your typical programmer-looking fellow with thick glasses. After we met, she told me about how he used to be fully blind from an accident and went to europe to get experimental surgery and is now able to see perfectly fine with the aid of glasses.

    I know of quite a few stories about people in areas outside of the united states received advanced medical treatment; this is the first I actually know personally.

    The really amazing thing about Jedi is that he could actually shoot a very good game of pool while blind. He would have his friend use a cue tapper and tap on the X/Y axis of the table to tell him where the object balls were at. I met him after he got his sight, but none-the-less an impressive feat.

    I would recommend to anyone interested in alternate surgies than what america has to offer to check into the european medical field and you may be surprised. I wish I had more information about him, if anyone is interested in any further information post in my journal and I'll get a hold of him.
  • A theory explaining why some nerves don't grow back is touched on in the article: it can cause more damage than good. They even noted that connections may have been a bit scrambled.

    Think about waking up after such a surgery and seeing only (the biological equivalent of) TV snow. Splendid. You may be able to tell when there is light in front of you (as you can tell when a TV that only displays snow is on), but I don't think the human brain is capable of forming a pattern out of gibberish.

    The same thing would happen in the case of a spinal cord injury - the density of nerves there is far too dense to guarantee they reconnect themselves properly. Think of waking up after spinal-cord reconstruction surgery to feel a large, shooting pain in your left leg. But in actuality, someone is tickling your right toe.

    For you computer people, think of severing a large bundle of wires or fiber optics with a backhoe. Instead of splicing each wire or fiber back together by hand, you decide it would work just as well if you just pushed it back together and hope each one connected to the one it was connected to before. Heh. Not likely.

    • ...but I don't think the human brain is capable of forming a pattern out of gibberish. you learned english. i've yet to see a more gibbered language =) (probably many others, i dont know many languages). many people listen to politicians and lawyers. i find their contributions to society along similar lines :^) you decide it would work just as well if you just pushed it back together and hope each one connected to the one it was connected to before. Heh. Not likely. nope, not when the system expects exact responce always, as computers often do. no matter how many times you try, a mis-formatted floppy will never register to windows. this is not how the brain works. it constantly reconfigures itself to different environments, trying to make sense out of what it receives. you could overwhelm it with junk though, and it'd never get it sorted out. but i'd imagine it could get something worked out in some cases, given time. (see the hand-thru-glass-door post a few messages up). cheers dakoda
    • hey, Dr. McCoy reconnected Spock's brain in a matter of hours. . . and he got everything right. . . .

      "very funny Bones, now please connect my penis."
  • They did this with horseshoe crabs a looooooong time ago. Now, setting aside that a horseshoe crab is more like a dinosaur than it is like a human, they were able to use a *sonogram* (yes, sound waves) to measure the electrical impulses of the thing's eyes (got me how they did it...) then sever and reconnect them with specially soothing frequencies or something like that.

    Human eyes are totally different, but the procedure has been done before...on a much less complex organism.
  • I used to live with a dude who was going for his PhD in Biology. His research was something related to this healing of optic nerves. He would take all these frogs and chop their optic nerves in different locations and then get them to somehow heal. The problem was, if he chopped the nerves in certain places, the nerves would heal incorrectly... the left eye's nerve would connect to the right's and vice versa. So then they would do these experiments to see if the frog could adjust to his new wiring. The funniest one would be to take one of these frogs, and put some food (a fly) in front of it, slightly off-center to the left for example. Since the frogs vision was reversed, the frog would hop to its right to try to get the food. I don't think any of them ever learned how to catch the fly after they were rewired.

  • Journal Article (Score:3, Informative)

    by dondelelcaro ( 81997 ) <don@donarmstrong.com> on Thursday December 06, 2001 @08:25PM (#2668330) Homepage Journal
    Fischer D, Heiduschka P, Thanos S.
    Lens-Injury-Stimulated Axonal Regeneration throughout the Optic Pathway of Adult Rats.
    Exp Neurol. 2001 Dec;172(2):257-72. [PDF] [idealibrary.com]

    Apologies to those who are unable to view the pdf. (If you're not on a campus who subscribes to idea library, I don't think you can access it.)

    Unfortuantly, these researchers still haven't purified the unknown factors that appear to be responsible for nerve growth. (They're in experimental opthamology... so it's not unexpected). Until these factors are purified and their functions described, nerve regrowth therapy will be difficult, if not impossible. Additionally, as some posters have pointed out, there are significant differences between rats and humans, and it remains to be seen if the same factors released by lens trauma are able to produce the same effects in humans or other model organisms. (But the posibility of non-applicability doesn't mean that rats and mice shouldn't be used, it just means that you need to test results obtained in them before applying them willy-nilly to other systems.)
  • Finally they punctured the lenses in the rats' eyes

    The old threat now seems like a remedy!

    Curious, do the lenses heal after the puncture damage? Seems like a sad trade to get your nerve back but lose the ability to focus.
    • Curious, do the lenses heal after the puncture damage?

      The authors claim that the lenses are ok after the trauma, but eventually cataract. (It's not really big deal to loose a lens, it just means that you'll definetly have to wear glasses afterwards...)

  • This is great! (Score:1, Insightful)

    by Thaidog ( 235587 )
    I have a point in the middle of my vision in both eyes where I can't see... similar to macular degeneration... perhaps this will lead to the growth of cones and rods transplants... I want my vision back!!!

  • Nothing particularly new... (Score:3, Interesting)

    by Elgon ( 234306 ) on Thursday December 06, 2001 @08:53PM (#2668459)
    I hate to rain on several respective parades but optical nerves, albeit from rat embryos, could be made to do grow back about 11 years ago: I knew this because I worked with a research group at Guy's and Tommmy's in London who did this while deciding what I wanted to do at university.

    The increased length is a bonus but not particularly important: They proved that the nerves formed synapses with the other nerves in the brain by shining light on the eye tissue and oberving the rats' pupils shrink in response.

    Otherwise, the article is excellent.

    Elgon
  • I suffered some nerve damage back in junior high many years ago. No, it wasn't from worthless teachers or bad food (although...). I had a wrestling accident in eigth grade. My right solder hit the mat in such a way to pull/pry the arm from the socket. Didn't feel to great. The good news is that I still wont the match, on points. The bad news is that tore the rhomboid muscle and stretched a brachial plexus nerve. The muscle is the muscle that sits at the base of your neck, more so on the back. With your right arm at complete rest, push in on the soft muscle a couple inches out from the spine on the back a couple inches below the top of the shoulder with your left hand. Not on the scapula, closer to the spine. Nice and soft, right? Ok, raise your arm just the slighest from the shoulder. Hard as a rock now isn't it? That's the rhomboid. Most of the arm function is lost when you injure that. The nerve I stretched runs around the backside of the shoulder to your hand. It controls things like touch, grip, etc.. of the hand (there are many nerves in that vacinity). I lost all feeling in my right hand by the next day. It came back a month or so later, fortunately. The doctor strongly warned against wrestling again because of the chances of me severing the nerve in a future accident. I wonder if treatment like this could have worked on my shoulder...
  • first make the rats blind? i'm sure that they could have used 3 blind mice to test it :)

  • Fingers (Score:3, Interesting)

    by stylewagon ( 197083 ) on Thursday December 06, 2001 @10:57PM (#2668909) Homepage Journal

    There was a recent incident here in Australia where an accident victims fingers were transplanted [smh.com.au] from one hand onto the other...

    One hand was severed during the accident, the other hand was crushed, they took the good fingers from the severed hand and put them on place of the crushed fingers. Wow.

  • I'm a graduate biochemistry student, and I work in a lab that does biochemical characterization of the crystallins of the lens of the eye. I am extremely skeptical of the theory that the crystallins are in some way mediating this response in the nerve cells.

    It is a long story, but the crystallins in the eye serve an essentially structural role. They're present in an absurdly high concentration in order to up the refractive index of the lens tissue. The proteins that evolution recruited to the lens were selected because they resist unfolding and aggregation at high concentration (and, one set of crystallins are thought to help with preventing aggregation of the other crystallins...).

    In any case, that tissue is just barely metabolically active (mature lens cells are non-nucleated), and the proteins present have, at most, only vestigal enzymatic activity. From everything we know about crystallins, there is no reason to think that they could ilicit this kind of response. They are highly stable, rather inactive proteins that evolved to last a long time and not mess with stuff.

    I don't dispute the study. I just think that the immune system response is a much more plausible explanation.

    !splut

Slashdot Top Deals

I tell them to turn to the study of mathematics, for it is only there that they might escape the lusts of the flesh. -- Thomas Mann, "The Magic Mountain"

Close