Anaesthesia is explained by solitons. Nerve membranes

have melting points, and once they are melted they

can't conduct sound.

http://www.eurekalert.org/pub_releases/2007-03/uoc-ot030607.php

http://arxiv.org/pdf/physics/0610147 (PDF only)

Another argument for solitons is that the electrical-only

propagation of nerve impulses would produce much more

heat that can be observed.

http://www.cbc.ca/news/technology/story/2007/03/09/science-nervessound-20070309.html

Regards,

Joachim

Really appreciate.

The so-called and so-accepted theory of electrical pulse propagation has got some pit-falls, and the soliton theory is explaining those. What I would like to think is if solitonic concepts can be fundamental in explaining the ways in which nerves work.

The characteristic feature of solitons is that they behave like particles in that they can pass each other and emerge with unchanged shape except for some shift in position.

This results from the nonlinear terms in the wave equation (eg KdV) counteracting the normal dispersion.

Nerve pulses on an axon also propagate according to a nonlinear wave equation. However, I doubt that nerve pulses can pass through each other like solitons because the local state is "refractory" after a excitatory pulse has passed, ie no new excitation is possible immediately after another one has passed.

Therefore, the soliton concept appears hardly promising to further "understand" the propagation of nerve pulses - at least along axons.

It might help if you could specify precisely what you are trying to understand beyond the wave equation, ie, the partial differential equations that governs the dynamics of the Na+ and K+ transmembrane potential profiles.

I enjoyed Joachim's witty response, however, it may have been meant to be taken with a grain of salt.

Have to see.

Thanks for your response Martin Burschka.

This discussion might benefit from a clear objective.

I see 2 main conflicting ones:

- Is there a grand theory of biological communication via sound at the nerve fibre level that needs to be implemented by believers? When we look for data that fits a "theory" that we have in mind, we will tend to stop when we have found what we have been looking for and, therefore, suffer from confirmation bias - like any TV-statistician close to some political party.

For a beautiful explanation of confirmation bias, see the book The Signal and the Noise" by Nate Silver. A marker of this approach is that the objective changes over time.

- Is there any phenomena that cannot be attributed to emerging from electrical nerve pulse propagation which is well understood. In that case, application of the current research of complexity to the brain may be a pipe dream before the microscopic phenomena are understood. For a beautiful description of a phenomena to be explained - including the complexity - see Edgar Allen Poe's analysis of "MAELZEL’S CHESS-PLAYER" (http://www.eapoe.org/works/essays/maelzel.htm).

This thread was started with a question about solitons - not acoustic nerve propagation.

Hi Shamit,

I do not quite understand yet where thermodynamics is relevant. to investigating brain function.

The laws of thermodynamics are largely concerned with equilibrium states and reversible processes including reversible detours for irreversible processes - all in macroscopic systems, beyond the mesoscopic scale of observable fluctuations.

The brain and the nerve fibres are certainly far from thermodynamic equilibrium and even in the absence of excitations, the linear kinetic equations reflect the absence of detailed balance, ie microscopic irreversibility.

I am not sure how abstract any definitions of temperature and entropy need to be to apply these to processes in the brain.

Hello Martin, hello Shamit.

First of all thanks for sharing these feedbacks. Lots have been found, investigated. But, when it comes to personal belief,I don't know if thermodynamics or soliton model can explain fundamentals of brain mechanisms.

It's my intuition that tells me to believe that somehow the brain information do or might do transmit via nonlinear way, and I think or rather I am forced to think by my intuition that it's SOLITON or somehow it's there.

Samit,

certainly, some nonlinear amplifying mechanism is necessary to keep the brain "thinking". This is what the action potential propagation along the nerve membranes is all about. Experimentally, it is readily accessible in the Squid giant axons (up to 1mm diameter), which is where I expect some acoustic propagation mechanism to be discovered first, eg, in form of some contractible fibres for amplification of some peristaltic kinetics.

The continuous electrochemical transmission of action potentials does have severe limitations in that acceptable propagation speed (necessary for survival of the whole animal) requires huge nerve diameters, and any "intelligent" brains based on this principle would not fit into our skull. So if there were an superior alternative mechanism, I would expect it to have dominated further evolution from the squids onwards.

Instead, the problem of signal speed and (free-)energy saving has been "solved" in vertebrates by electrically isolating sheaths (Schwann cells) that make the excitation jump from one relay station (Ranvier) to the next. Therefore, based on my intuition, I do not keep my breath, waiting for the discovery of acoustic signal propagation.

BTW, calling this "intelligent" design would mean to transcend the scope on which intelligence is scientifically defined, ie, as a human trait.

Non-equilibrium thermodynamics means to me that there is a level of description similar to Navier-Stokes equations where there is local equilibrium.

This may apply to both sides of the membrane, as long as the channels are closed., Once the ion-channels in the membrane open, we are locally far from equilibrium on the scale of discrete molecules and even the idea of a one-dimensional geometry (x=distance from the membrane, homogeneity along y,z) may not apply.

Are you aware of any simulation of an ion-channel including the ion-diffusion and electric potential field over time? Present simulation programs may be up to this.

How could I help?

No need to look at any opalescence near any critical point, afaik.

I do not see any connection to the brain yet.

My humble suggestion for a research proposal:

Could this effect be exploited to stimulate nerve growth mechanically?

The 'soliton model' has a couple of credentialed people pushing it. Nonetheless, it is crank science. The primary justification--that the action potential propagates 'adiabatically'-- is wrong on fact and logic. The model does not account for the major features of action potentials, including ionic selectivity and pharmacology. It has been around for a decade and has attracted no support beyond its authors. 

Here is a link to an answer I wrote earlier on the Quora site.

http://www.quora.com/Are-nerve-impulses-solitons

To Roman,

Can you elaborate more on this...like the nature of the possible soliton dynamics.

Hello!

You might get some insight through this article which talks of thought as a soliton. https://nariphaltan.org/thoughtgravity.pdf