Scientists Say Nerves Use Sound, Not Electricity 382
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.'"
So when a tazer hits you (Score:5, Funny)
Wow... who would of guessed it!
einstein
http://anarchy-tv.com/ [anarchy-tv.com]
Re:So when a tazer hits you (Score:5, Funny)
Re:So when a tazer hits you (Score:5, Insightful)
That wouldn't prove sound controls nerves, for it is quite common knowledge that doing something like that would upset your middle ear, so you'd lose balance and become nauseous just because of that.
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Electrical impulses are the flow of electric charge.
They are completely, 100% different physical phenomena.
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It _could_ be that the electricity is exciting the nerves and, in turn, they are sending signals(by sound)...causing loss of motor control.
Re:So when a tazer hits you (Score:5, Informative)
Re:So when a tazer hits you (Score:5, Interesting)
Re:So when a tazer hits you (Score:5, Insightful)
Re:So when a tazer hits you (Score:4, Funny)
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Re:So when a tazer hits you (Score:4, Insightful)
It's quite simple, really. (Score:5, Insightful)
Re:So when a tazer hits you (Score:5, Insightful)
I'll believe it when I see experimental evidence: but the article as presented is pretending that God makes timepieces himself because you found a watch in the desert. It's nonsense.
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Moreover, "heat produced by electrical conduction" and the like have to come from somewhere. The amount of energy processed by a cell is limited mostly by glucose metabolism. (We could chat about protein metabolism as well, but let's not get distracted.) That glucose
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I call bullshit, and I want whatever this group of Danish scientists are smoking. I'm betting trips to Amsterdam are de rigeur with these folks.
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Raised eyebrows... (Score:5, Interesting)
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.
Re:Raised eyebrows... (Score:5, Informative)
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Indeed, if it were true, I could shout at my hand and either I'd feel something or it would twitch or something. Sound waves permeate tissue way, way too easily to be isolated. This may be the most ludicrous article I've ever not read. :-D
Re:Raised eyebrows... (Score:5, Informative)
Either way, the summary and the linked article look to be way off base.
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And while much good research is published all over the place, this is so groundbreaking that it would be a Nature paper if good enough. Nature/Science/etc publish good, "exciting" papers. Other journals publish good papers that just aren't high-profile enough for the top impact journals.
Re:Raised eyebrows... (Score:5, Informative)
I can't but agree.
I and my collegues did a research on the relationship between two distant methods of protein function regulation. We thought it was pretty nice, so we sent it to a bunch of very high-impact journals. Most of them sent it back even without giving it to referees. The only one that did refused us because we had a bad referee, and refused to even read our (long and detailed) response to his/her comments. So, less than year ago, we ultimately settled for a good but not top-most journal, where it was warmly accepted.
A couple of months ago my group leader talked at a conference in USA where he talked also about the research in that article. An editor of one of the journals we tried to publish that more than a year ago came to my boss and said "Really nice and hot work, why don't you publish it for us?" The answer: "Because you didn't want it a year ago, and now it's already done."
Why this sudden change? Because our proposed mechanism was not even a blip on the radar when we did it. In the meantime a recognized leader of the field published on Science a work that independently hinted in the same direction (even if in a very different and even less interesting way), and only because Mr.Guru created the buzzword now we are beginning to be taken seriously. Really sad.
So... (Score:5, Funny)
Re:Raised eyebrows... (Score:5, Informative)
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
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Read the original before objecting. (Score:4, Informative)
First, the Biophysical Journal is fairly respectable, and a much more appropriate place to publish work in this area. Second, the actual journal article in the Biophysical Journal does NOT say what the Slashdot and CBC titles say, so judging them on this basis is inappropriate. The article is an extension of a previously published model which shows that nerve signal propagation can be described as 100m/s piezo-electric soliton pulses, and it shows that these are dependent upon the phase transition temperatures for membranes.
Re:Raised eyebrows... (Score:4, Insightful)
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Re:Raised eyebrows... (Score:4, Informative)
Well, the one meter per hour figure refers to the drift velocity. The electrons aren't actually flowing like water in a stream, they are bouncing around like mad at speeds much faster than one meter per hour but they have a slight tendency to drift in the direction of higher voltage. Averaged out, this drift velocity is very small but the electrons themselves are moving much faster.
I think this is why so many people get confused by electricity. The FIELD moves almost the speed of light, but it makes electrons drift very slowly, even though the electrons THEMSELVES are moving rapidly. It's all very hard to visualize at first.
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Bo
Re:Raised eyebrows... (Score:5, Informative)
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.
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Seems to me that when you said "in the strictest sense of the word" you put the word of the law above the math of the law. Since we're talking about a change in EM propagating through space we're dealing with AC rather than DC, and when dealing with AC we're dealing with the EM fields and not the charged particles mediating the fields. The EM fields of course move at c, and since the signals propagating through the nerves move a lot slower than that, we probably should concl
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Re:Raised eyebrows... (Score:5, Insightful)
There are plenty of valid criticisms you can bring to the HH model. It cannot account for all observations (there was a paper in Nature recently exactly to this point) and after all, when you try to model primate cells with HH dynamics, you are in effect comparing your monkey with a giant squid! It has tbh always amazed me how well that worked at all. So if you're going to say, HH is inadequate, that's fair. If you are going to say that non-electrical pathways for transmitting information exist alongside the known electrical currents, that's also fair and you have my complete attention. But you can't just say that nerves don't use electricity, that just labels you as someone trying to be sensationalist. Besides, if you could prove this beyond reasonable doubt, you should and would send the paper to Nature.
Then again, this is my reaction to the
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Re:Raised eyebrows... (Score:5, Informative)
http://www.biophysj.org/cgi/rapidpdf/biophysj.106
They build upon Meyer & Overton's work & specificly say that Hodgkin-Huxley is not satisfactory with relation to anestethics.
My question is: Does the Meyer-Overton rule mean that elephant tranquilizers are 10,000 more times soluble than morphine?
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The Meyer Overton Hypothesis specifically relates to volatile (inhaled) anaesthetic agents, and NOT morphine which clearly has a receptor based mechanism of action. It's not correct to use the hypothesis for drugs such as opioids, or barbiturates (eg: thiopentone/pentobarbital), for which a receptor based mechanism of action has been established.
So, no, it doesn't predict the potency of most drugs, just the inhaled ones whose potency is directly proportional to solubility in octanol or olive oil.
Re:Raised eyebrows... (Score:5, Interesting)
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).
Re:Raised eyebrows... (Score:5, Funny)
Is this an example of the fabled neuroscientist humor?
Re:Raised eyebrows... (Score:5, Funny)
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Because all of that is explained by their model, as outlined in their first [pnas.org] and second [biophysj.org] articles.
In short, it goes like this: by dissolving in the membrane, anestheti
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There isnt any actual evidence that it is sound.
If it is sound then whats the magic frequency to cause the loss of muscle control?
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More to the point, there's no philosophically valid way to "prove" anything conclusively.
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Re:I agree, this is BS (Score:3, Insightful)
To illustrate, his most compelling argument is this: "The physical laws of thermodynamics tell us that electrical impulses must produce heat as they travel along the nerve, but experiments find that no such heat is produced."
This was when I thoug
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Shh (Score:2)
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Re:Shh (Score:5, Funny)
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Might be mistaken... (Score:4, Interesting)
What a bad summary. (Score:3, Insightful)
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Nerves do not transmit by electricity (so current teaching is false): 3 times
Nerves actually transmit by sound: 2 times
Uh. (Score:3, Insightful)
I'm so tired of hearing the press use "scientists say" as a legitimizing opener. If you believe something because "scientists" say so, you are probably not a scientist. If you were, you would be forced to know many scientists who are idiots; scientists who no one should listen to.
Peer reviewed and agreed upon usually means good science. The CBC saying, "scientists say" means squatcum.
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Next up? "Scientists say light bulbs use sound, not electricity"
If you believe something because "scientists" say so, you are probably not a scientist
You're probably a politician...assuming the scientists in question are ones who work for the people who give you money...
Bwha? (Score:5, Insightful)
Extraordinary claims require extraordinary evidence.
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i.e., the electrical pulses are part of the process of communication not an encoding of information itself.
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Could be both? (Score:2)
Conspiracy theory alert: (Score:5, Funny)
Will you guys quiet down! (Score:5, Funny)
Ryan Fenton
TFA is completely innacurate (Score:5, Informative)
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.
Re:TFA is completely innacurate (Score:5, Interesting)
(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.
Re:TFA is completely innacurate (Score:5, Informative)
(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) [nih.gov] 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.
An article by one of the members of the res. group (Score:2)
Anyway, you can read that article in its entirety here: http://www.gamma.nbi.dk/Galleri/gamma143/nerves.p d f [gamma.nbi.dk]
IANANS (guess...) but I do find it very agreeable that it is odd that strength of
Re:An article by one of the members of the res. gr (Score:2)
Re:An article by one of the members of the res. gr (Score:3, Informative)
So you're willing to accept this on something as coincidental as the strength of a drug being proportional to its lipid-solubility? Wow.
Every cell in your body is encapsulated by a cell membrane that is essentially two layers of lipids. It's not a real revelation that many drugs' effe
Like the Internet (Score:3, Insightful)
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Chalkboard, anyone? (Score:2)
If that's the case... (Score:4, Funny)
You turn into Ozzy Osbourne?
That explains why.... (Score:2, Funny)
It's not because I'm drunk, It's involuntary movements caused by the sound, Some "scientists" said so!
It would explain the Brown Sound... (Score:2)
Mind control? (Score:5, Funny)
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Move along...
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Earplugs? (Score:4, Funny)
Does this mean that the next time someone kicks me in the nads all I need are earplugs for the pain to go away?
I don't think I will test that theory, I'll let someone else do it.
I had to check the calendar... (Score:2)
*I* want some of what *THEY* are smoking...
--Tomas
You know... (Score:3, Insightful)
The famous saying is fitting. (Score:2)
these people are nuts (Score:3, Informative)
Now, it's always a good idea to keep an open mind. But these people have presented no even remotely interesting evidence that we need a change in paradigms. They are simply nuts.
Feh! I'm not wasting my mod points on this! (Score:2)
Both are wrong. (Score:2)
A single nerve cell transmits information by having a depolarized zone travel down the axon, which is an electrochemical process.
Information travels between nerve cells through synapses, which can either be chemical (using a neurotransmitter) or "electric" (electrochemical).
So if these guys claim that biology and medical textbooks talk
impossible!! (Score:2)
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meh. Nevermind, probably wasn't as funny as I thought...
Why did the Galvani experiment work? (Score:2)
So does it mean that... (Score:4, Funny)
On to the net nerve (Score:3, Informative)
Also, we listen to brain waves with an EEG or MEG, which measure minute electrical or magnetic impulses. We do not use a microphone and amplifier. Plus, we induce currents with electricity and magnetism, not loudspeakers, and produce predictable results.
Sound waves of sufficient intensity to propagate the full length of a nerve would be so strong in the main trunk that they'd disrupt the transport mechanism carrying neurotransmitters down from the cell body. They'd isloate the nerve from participating in the local neural network.
A new theory should explain everything just as well as the old plus more. This one falls apart at the basics and can't handle some of the nuances.
If sound propagation were the key, all that sodium and potassium gating to change the local membrane charge would be useless, and nature hates that kind of waste.
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As a soliton travels down a membrane, the density and thickness change. Since the membrane is full of charged and polar molecules, changing its density and thickness will generate an electric signal that can be detected.
No, because the sound wave is assumed to be created piezo-electr
neither sonic nor electric: TFA oversimplifies (Score:4, Insightful)
Just looking at the transmission speeds makes it clear what is going here:
Data:
Summary: neural transmission is orders of magnitude too slow to qualify as either an electrical or sonic phenomenon.
Conclusion: TFA suggests replacing one gross oversimplification of neural transmission with another. Neural transmission might have some qualities of both but is clearly neither. TFA is garbage.
Note Bene:There is no way of knowing what the original work was talking about. I cannot imagine anyone who has studied neural transmissions saying anything like TFA's contents. I suspect that the author of TFA was presented with an anology and took it for fact.
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Once, when I tore the ligaments in my hand, they went over the area with an ultrasonic gadget that was seriously ultra - it was in the 2 to 3 MHz range.
Surely either of those would have excited or swept past the frequency that nerves allegedly transmit at?