Scientists say nerves use sound, not electricity

[Dominus Atheos]

CBC

The common view that nerves transmit impulses through electricity is wrong and 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.

"For us as physicists, this cannot be the explanation," said Thomas Heimburg, an associate professor at the university's Niels Bohr Institute. "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."

Heimburg, an expert in biophysics who received his PhD from the Max Planck Institute in Goettingen, Germany — where biologists and physicists often work together in a rare arrangement — developed the theory with Copenhagen University's Andrew Jackson, an expert in theoretical physics.

According to the traditional explanation of molecular biology, an electrical pulse is sent from one end of the nerve to the other with the help of electrically charged salts that pass through ion channels and a membrane that sheathes the nerves. That membrane is made of lipids and proteins.

Heimburg and Jackson theorize that sound propagation is a much more likely explanation. Although sound waves usually weaken as they spread out, a medium with the right physical properties could create a special kind of sound pulse or "soliton" that can propagate without spreading or losing strength.

The physicists say because the nerve membrane is made of a material similar to olive oil that can change from liquid to solid through temperature variations, they can freeze and propagate the solitons.

The scientists, whose work is in the Biophysical Society's Biophysical Journal, suggested that anesthetics change the melting point of the membrane and make it impossible for their theorized sound pulses to propagate.

The researchers could not be immediately be reached for comment.

[Zac Naloen]

So how are these sounds produced?

And why does electricity cause the bodies nervous system to get confused and freeze up?

[AMX]

And how do they explain certain neurotoxins that work by blocking ion channels?

Also, I'm pretty sure the electrical pulses have actually been measured...

[Straha]

So how are these sounds produced?

And why does electricity cause the bodies nervous system to get confused and freeze up?

And to turn the question on its head why the hell doesn't sound (or any vibrations placed nearby nerves) do the same thing to the body?

[Xon]

And how do they explain certain neurotoxins that work by blocking ion channels?

Also, I'm pretty sure the electrical pulses have actually been measured...

There is an entire freaking method of measuring brain and nerve activity by sticking what amounts ot hypersensitive aerials to people's skin. That stuff is used to measure if electrical siganals are getting from the brain to the nerves & vise-versa.

[Shroom Man 777]

Are MRIs actually giant listening devices?

[Dooey Jo]

So, they failed to measure any heat, and therefore concludes that it cannot be electricity, even though we can measure electrical fields from the brain and nerves? How would sound produce such fields? Why can we hook up neurons to interfaces without using speakers and microphones? This seems pretty fucking ridiculous. Perhaps these guys ventured a little bit too close to Christiania and inhaled a bit too much of the fumes from that place.

[Admiral Valdemar]

The day a physicist speaks with any authority on biology will be strange one indeed. Pay them no heed, they know not of what they speak given their one unfounded criterion is blown away by so many other electro-chemical proofs as to be folly.

[Rye]

Physics really does seem to attract more "idiot savant" types than good old chemistry and biology. I have to wonder if they're just intentionally dense and are doing this as a thought experiment or if they really are just stuck in the autistic border world between reality and the math representation of it all.

[andrewgpaul]

Aren't the electrical signals only between nerve cells, with the signal inside the cells transmitted by chemical diffusion? (or possibly the other way around). If so, that might explain the results of his experiment.

[AMX]

Aren't the electrical signals only between nerve cells, with the signal inside the cells transmitted by chemical diffusion? (or possibly the other way around). If so, that might explain the results of his experiment.

Other way round.

[Grand Moff Yenchin]

I've been patching electrodes on neurons for nearly a whole year, I guess I was wrong all the time, they're actually minature mikes

[Thinkmarble]

As far as I see this is a news article.
Which means that the original result can be anything including the opposite.
Pay no heed.

[Admiral Valdemar]

It's being placed in a journal, but whether the peer reviewing goes well is another thing entirely. Most press articles on science go for the most controversial and often quite old pieces that were found and debunked long ago by readers of New Scientist or Focus.

[Fingolfin_Noldor]

The day a physicist speaks with any authority on biology will be strange one indeed. Pay them no heed, they know not of what they speak given their one unfounded criterion is blown away by so many other electro-chemical proofs as to be folly.

Actually, the field of Biophysics is quite growing at the moment.

[R. U. Serious]

Here is the press release from the university:
http://www.ku.dk/english/news/nerve_soundtrack.htm

And the paper itself seems to be available as a pdf as well:
http://www.pnas.org/cgi/content/abstract/0503823102v1

It doesn't look like the news-bite from the OP diverges much from the two sources, but then again, most of that stuff is over my head.

[R. U. Serious]

Oops, the link to the pdf is to an older paper, there seem to be a couple more recent ones:
http://membranes.nbi.dk/publications.html

[Darth Wong]

If nerve signals are carried by sound vibrations, how are they interfaced to the brain, which is known to work on electrical impulses? Or are they going to say that inter-neuron communication is also sonic in nature, which would beg many other questions regarding discoveries made in the field of neurology? And why doesn't the use of ultrasound cause involuntary convulsions, the way electrical impulses can?

[R. U. Serious]

The slashdot thread even had the link to the actual paper the news is based on:
http://www.biophysj.org/cgi/rapidpdf/bi ... 9754v1.pdf

[Lord of the Abyss]

"For us as physicists, this cannot be the explanation," said Thomas Heimburg, an associate professor at the university's Niels Bohr Institute. "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."

Wouldn't sound also produce heat ? I'd think that the movement of molecules as the sound wave passes would cause friction between them, and that makes heat. I've certainly never heard sound proposed as a loss free method of energy transmission before.

[Admiral Valdemar]

"For us as physicists, this cannot be the explanation," said Thomas Heimburg, an associate professor at the university's Niels Bohr Institute. "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."

Wouldn't sound also produce heat ? I'd think that the movement of molecules as the sound wave passes would cause friction between them, and that makes heat. I've certainly never heard sound proposed as a loss free method of energy transmission before.

Yes, anything that produces vibration can apply heat to the surroundings if energy is being added like from some nerve signal. So unless they're instruments are really not fine-tuned for the level of temperatures expected, they're just full of shit.

Though that's just one hole, the others are vast as it is, from personal experience with measuring cell signalling via electrodes that, shock horror, measure electrical voltage, not sonic resonance. Nerves just have a combination of electrical and chemical signalling pathways due to the nature of the CNS/PNS.

[Aaron]

I had a nerve function test (forget the real name of it) done a number of years ago, they stick a needle in your arm and shock the nerve and then measure the voltage coming off it at a different point. I have a hard time seeing how that would work if nerves used sound, or why my arm was twitching in response to the current.

[Superman]

If nerve signals are carried by sound vibrations, how are they interfaced to the brain, which is known to work on electrical impulses? Or are they going to say that inter-neuron communication is also sonic in nature, which would beg many other questions regarding discoveries made in the field of neurology? And why doesn't the use of ultrasound cause involuntary convulsions, the way electrical impulses can?

The anatomy of the heart also functions to produce electrical impulses. It's commonly referred to as its conduction system. The sinoatrial node creates an electrical impulse, which then stimulates another muscle, causing it to contract.

[Battlehymn Republic]

Physics really does seem to attract more "idiot savant" types than good old chemistry and biology. I have to wonder if they're just intentionally dense and are doing this as a thought experiment or if they really are just stuck in the autistic border world between reality and the math representation of it all.

Hm. Are there rivalry between the sciences? On the boards there have been some bashing of mathematicians. Though to be fair, the mathematicians in question were historical revisionists and ID-ers. And any scientist that tries to make claims about another branch's facts will get smacked, even if they're Freeman Dyson.

[mr friendly guy]

"For us as physicists, this cannot be the explanation," said Thomas Heimburg, an associate professor at the university's Niels Bohr Institute. "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."

Wouldn't sound also produce heat ? I'd think that the movement of molecules as the sound wave passes would cause friction between them, and that makes heat. I've certainly never heard sound proposed as a loss free method of energy transmission before.

When I first read that as well, it was also my thought. The other thought was screaming bullshit, quite loudly as well.

I had a nerve function test (forget the real name of it) done a number of years ago, they stick a needle in your arm and shock the nerve and then measure the voltage coming off it at a different point. I have a hard time seeing how that would work if nerves used sound, or why my arm was twitching in response to the current.

It could be either an EMG or a nerve conduction study that you are thinking about.

On the article itself, excess or low ions can affect nerve conduction. The movement of ions intra and extracellularly cause an electric current known as the action potential.

Lets say for arguments sake that nerve conduction works by sound. Not only does this hypothesis also fails to explain why no heat is produced since by thermodynamics heat must also be produced by sound, it also can't explain how excess ions can fuck up conduction. For example high and low potassium causes cardiac arrhythmias. High calcium cause loss of reflexes (which involves nerve conduction as part of getting the reflex).

In short, Niels Bohr the great Dane and one of the "fathers" of quantum theory must be writhing in his grave after this embarrassment by his institute