Slashdot Mirror

← Back to Stories (view on slashdot.org)

Scientists Say Nerves Use Sound, Not Electricity

Posted by ScuttleMonkey on from the just-hard-of-hearing-all-over dept.

gazzarda writes "The CBC is reporting that a team of Danish scientists are claiming that nerve impulses are transmitted by sound and not electricity. 'The common view that nerves transmit impulses through electricity is wrong and that they really transmit sound, according to a team of Danish scientists. The Copenhagen University researchers argue that biology and medical textbooks that say nerves relay electrical impulses from the brain to the rest of the body are incorrect.'"

19 of 382 comments (clear)

  1. So when a tazer hits you by Anonymous Coward · · Score: 5, Funny

    ...its really the sound of the tazer that is making your muscles contract in all kinds of ways and you losing motor control, not the hundreds of thousands of volts coursing through your body.

    Wow... who would of guessed it!

    einstein
    http://anarchy-tv.com/

    1. Re:So when a tazer hits you by Anonymous Coward · · Score: 5, Funny

      There is only one real way to test this: put your head in a large bell and have someone ring it as loud as they can. If you lose all muscle control and are confused for a minute or so afterwards it would then prove that it is sound that controls nerves. Otherwise I suggest that we put a researcher in a specially made chair that will deliver high current directly through an electrode placed on the top of the head (and another somewhere else such as the wrists). If the researcher loses all muscle control then it also confirms that electricity controls nerves.

    2. Re:So when a tazer hits you by LanceUppercut · · Score: 5, Insightful

      You need to take "Logic 101" classes. Just because muscles react to electricity (and body transmits electricity) does not prove in any way that it is necessarily electricity that is used by body to control muscles. In the same way one can conclude that just becuase body reacts to bullets means that it uses bullets internally, which is nonsense.

  2. Raised eyebrows... by BWJones · · Score: 5, Interesting

    As a neuroscientist who has a healthy respect for a little anarchy from time to time, I have to call shenanigans on this one. I'd love to kick down the doors on some fundamentally held beliefs (my dissertation did something close to that), but this had me laughing out loud.

    I've recorded from nerve cells in the classical manner and run the parametrics on different ionic concentrations and it would take quite a solid argument backed up by data for me to displace any of the credibility built on the classic Hodgkin and Huxley work.

    --
    Visit Jonesblog and say hello.
    1. Re:Raised eyebrows... by myc · · Score: 5, Informative

      IAAANS (I am also a neuroscientist) and I'm with you on this. TFA sounds pretty crackpot to me. If they really had strong evidence for this it would be published in Nature, not Biophysical Journal.

      --
      NO CARRIER
    2. Re:Raised eyebrows... by Anonymous Coward · · Score: 5, Interesting

      As another neuroscientist, I would urge you to keep an open mind. Perhaps they mean the frequency of events fall neatly into the sound frequency range: i routinely see 20-200 Hz E/IPSC at RT, and much higher in larger neurons at 37'C. You can get action potentials at up to 1000 Hz in auditory neurons.
      If anything, try plugging in a speaker into your patch-clamp amplifier's audio port and see how it sounds (Back in the days I would directly convert the frequency and amplitude of the events in my voltage-clamp traces to raw PCM and play that out, and it sounded like some kind of a pothead techno mix tape, something you could definitely listen to and even enjoy.

      Certainly, the movement of ions across the membranes is what drives most neurons (forgetting about the slower metabotropic communication, kinases, etc. for a second), but perhaps thinking of these in terms of frequencies would help non-math people appreciate the neuronal communication (the concept of a choir singing in a labyrinth is a lot easier to grasp for a layman than even the most basic HH multivariable d.-equation models).

    3. Re:Raised eyebrows... by Kahai · · Score: 5, Funny

      I'm also a neuroscientist and I'd like to say I find this research credible and also true. Sincerely, Essjay

    4. Re:Raised eyebrows... by anaesthetica · · Score: 5, Funny

      As another neuroscientist, I would urge you to keep an open mind.

      Is this an example of the fabled neuroscientist humor?

      --
      The Rise and Fall of Online Community
    5. Re:Raised eyebrows... by thrawn_aj · · Score: 5, Informative
      Note: I think the main link in this thread has incorrectly summarized the article. I just read the original article and the headline is just plain wrong IMO. I tried to give my interpretation of this work here:

      I will say that their physics seems reasonable - one should understand that when we say "sound" there can be several meanings to that word. In the article, they are talking about piezo-electric pulses which I can visualise as a pressure wave that creates voltages between synapses (forgive me if I'm murdering the biology here ;-)). Imagine your usual piezo-crystal (a simple example is the one in a wristwatch) that vibrates (pressure waves) when a voltage is applied. Well, the reverse can also happen (this is used in some species of microphones). The way I visualize their model is that a piezo-electric soliton (if I remember my group theory, it's a sort of a quantized sound wave which persists without being destroyed by background noise because it has a topological quantum number asociated with it) travels between synapses leading to a voltage between them. Now, the pressure wave exists in the surrounding medium, which contains the ions in solution. So, at the most one can interpret these findings to mean that neural conduction is more like current in a superconducting wire than electroplating :D. This is the essence of their transport theory (as I understand it).

      Another thing to note is that the article is not written as a maverick physicist would. It is written in a way that only a proper experimental physicist would - theory -> prediction -> experiment -> comparison. And the thing they are evaluating is actually the effect of anasthetics on neural transport. So, they are simply not claiming stuff as the news site falsely overhypes. I for one find this article fascinating even though biophysics is not my field.

      I don't see how this translates to the sensationalist headline (although it's not the poster's fault, the linked site is a Canadian news site. The fact that it's Canadian is irrelevant :D, but the fact that it's a news site is rather telling. Also, they couldn't reach the authors for comments, which probably explains the awkward spin on the research.

      IAAANS (I am also a neuroscientist) and I'm with you on this. TFA sounds pretty crackpot to me. If they really had strong evidence for this it would be published in Nature, not Biophysical Journal.

      I'm afraid Nature is rather conservative in that respect and their editorial policy is at least partly based on maintaining or raising their impact factor (it is a highly profitable publication after all). The only way they can do that is by ensuring that only articles that are likely to be frequently cited in the future are published (that's the critical number that figures in the calculation of impact factor). As a result, the argument that any ground-breaking research would be automatically published in Nature is simply not true. Quite the contrary in fact. Now, before people mistake this for flamebait :P, I'm simply saying that Nature prefers the "wait-and-watch" routine, sorta like the Nobel committee, which is notorious for awarding A. Einstein with the prize for the photoelectric effect and not special or general relativity :P. I'm sure Nature will publish these guys a few years down the road after they have garnered enough of a reputation (IF they are correct that is!).

      I was just trying to point out the decisions involved in publishing with Nature. If people want to publish something quickly that will spur interest and spawn more research in that particular area, they do NOT publish in Nature; rather they would publish in a more "everyday" journal like Biophys. A Nature publication (unless you research frogs; for some reason frogs are hot in NATURE =D) is sorta like a fine wine. You just can't afford to waste time on it everyday ;). Plus, its rather dishearten

    6. Re:Raised eyebrows... by jabuzz · · Score: 5, Informative

      IAAP (I am a physicist) and an electical current is the movement of electrical charge. Consequently your "electrochemical state changes that propagate along nerve axons" are in fact electrical currents in the strictest sense of the word. When we have moving charge we have a current end of discussion.

      The fact the propagation speed is much lower than when the electrical charge is an electron and the medium is a metal is entirely irrelevant. Lots of mediums exist that propagate electical current at much slower speeds than metals. I would also point out that propagation speed of an electrical current bears no relation to the velocity of the charge carriers either.

  3. Bwha? by lazybratsche · · Score: 5, Insightful

    How do they explain all of the electrical measurements of nerve cells? We have measured voltages and currents. We know that these are dependent on certain protein channels, and salt concentrations. If impulses are actually the result of "solitons", how can they explain half a century worth of neurobiology? One wild guess, based on a minor inconsistency (if it even exists as they believe) needs a hell of a lot more evidence before they should be taken seriously.

    Extraordinary claims require extraordinary evidence.

  4. Conspiracy theory alert: by Glowing+Fish · · Score: 5, Funny

    Time to replace all your tinfoil helmets with a pair of ear plugs.

    --
    Hopefully I didn't put any [] around my words.
  5. Will you guys quiet down! by RyanFenton · · Score: 5, Funny

    "Hey - will you guys quiet down? I can barely hear myself think!"

    Ryan Fenton

  6. TFA is completely innacurate by lazybratsche · · Score: 5, Informative

    On further review, it seems that the CBC article is total crap, but that the original paper isn't that far off the deep end. I admit that I don't know enough to really follow or critique the research, but it doesn't seem to be the crackpot theory that TFA implies. Nowhere, for example, does that paper say that nerves don't use electricity. In fact, the paper refers to "solitons" as a piezo-electric effect. They are merely proposing a new mechanism on top of previous theories, not trying to completely throw out all neuroscience to date.

    To recap: Completely bogus headline, based on a completely bogus bit of popular science reporting, which itself is based on a possibly intriguing (but tentative) bit of original research. Nothing to see here.

    1. Re:TFA is completely innacurate by myc · · Score: 5, Interesting

      BTW, IAANS (I am a neuroscientist). Here is another link to their earlier research on this. While PNAS is certainly a reputable journal, I made some interesting observations while reading their paper:

      (1) It's very physics- and modeling-heavy. While I don't like to generalize, my impression has always been that physicists are not very good biologists. I've been to many a "cross-disciplinary" seminars where physicists try to model biological processes, and inevitably they make very little biological sense.

      (2) They cite mostly old papers from the literature (1960s) that point out deficiencies in the Hudgkin-Huxley model (although it's true that the HH model of action potential propagation may have become dogmatic).

      (3) It was published via track I in PNAS, wherein a Member of the National Academy of Sciences can directly accept the paper for publication, bypassing peer review. The purpose of this mechanism is so that controversial works have a chance to be published; historically, it has been used to dole out favors and/or to publish crackpot theories.

      Ultimately, while what they are proposing is not as crazy as TFA makes it out to be, the paper sounds to me that they are trying to make a mountain out of a molehill. Neuroscientists today have a very detailed understanding of how axonal neurotransmission works. The authors claim that the solitons (sound waves) in their model explain how nerve propagation in myelinated axons can be much faster than in equivalent non-myelinated axons, but again, neuroscientists are fairly sure they understand myelination in the context of the HH model. Even if axons go through soliton mediated pulses on the membrane that are in phase with action potentials (which is what they claim to observe), I seriously doubt that it has any physiological relevance, since just about everything neurons can do can be explained by ion flux through channels.

      --
      NO CARRIER
    2. Re:TFA is completely innacurate by abes · · Score: 5, Informative
      Just to add to this, for people who are confused:

      (1) Hodgkin and Huxley (1952) postulated the existence of transmembrane proteins that allowed conductance of ions in and out of the cell. They showed, using a giant squid axon, that action potentials are composed of a sodium current and a potassium current. While they had no way to directly observe the channels that allowed these currents to flow, using curve fitting, they worked out the general dynamics of these channels.

      (2) Sakmann and Neher (1976) showed the existence of these channels by developing the whole-cell patch clamp technique. Single channels have been observed and characterized using this method (and employed by many labs).

      (3) The term 'tranmission' is sometimes used in a confusing manner in neuroscience. In this case, as pointed out by the parent, transmission is down the axon of a single cell. Mylen sheaths can form around the axons of cells in order to speed up transmission. This can also occur by making the axon diameter wider. One interesting difference between vertebrates and invertebrates is that appearance of the mylen sheath with the advent of the backbone. This allows for cells to take up less space (so more can be packed into a given volume).

      Another form of transmission of signal is between cells. This is usually done by chemical synapses. Chemical synapses work by the presynaptic cell releasing chemical into the synapse, the chemical ligand binding to receptors on the postsynaptic cell, and causing either an ionic flux (ionotopic channels) or a chemical cascade (metatrobic channels).

      Somewhat recently there has also been discovered electrical synapses in the mammalian brain. These seem to be between inhibitory cells of the same type.

  7. Mind control? by JimXugle · · Score: 5, Funny

    Imagine all the possibilities! You could make someone do something just by yelling at them loud enough!!

    --
    -jX

    Don't you just love politics? It's like a comedy of errors.
  8. So... by thrill12 · · Score: 5, Funny

    ...can we say officially that this part of slashdot has become a FANSCOS now (First Annual NeuroScientist Convention On Slashdot) ?

    --
    Slashdot: stuff for news, nerds that matter, matter for news, stuff that nerd
  9. It's quite simple, really. by The_mad_linguist · · Score: 5, Insightful

    Insightful gives karma, funny doesn't.