Soliton model of the action potential

[madness]

Has anyone else come across the soliton model of the action potential?

https://en.wikipedia.org/wiki/Soliton_model_in_neuroscience

It seems extremely non-mainstream, especially given that it presented as an alternative to the Hodgkin-Huxley model, which is undoubtedly the most successful theoretical model in all of neuroscience. But perhaps there is also something to this soliton model, in explaining certain additional biophysical properties of action potentials? There are cerainly a number of papers in good journals about the soliton model.

 

[jim mcnamara]

You can see in the Wiki article all of the objections, studies where the model fails. Since this is not my area, I would assume it was somebody's Pet Hypothesis that got spread more because of the original author than any great scientific merit.

Nutrition studies are rife with this kind of problem - papers on both sides, some right, some wrong. The problem: You cannot change documented Biochemistry and Physiology, but there are standard nutrition guidance recommendatons that accomplish this feat. It took 25+ years to get the US FDA to ban, in effect anyway, trans fats. Trans fats were a boon to the food industry. Foods can still have small amounts of it. Less than 1 gram per serving. Reduce the food serving size, and voila, zero trans fats on the label.

I am going to ping @Pythagorean who seems knowledgeable in this area.

 

[madness]

I agree, and I'm not out to defend the soliton model, but I'm curious if solitons can coexist with the classic Hodgkin-Huxley mechanism for action potentials. This recent article seems to say so:

https://www.nature.com/articles/ncomms7697
https://www.theguardian.com/science/neurophilosophy/2015/may/01/action-waves-in-the-brain

Perhaps the original soliton model went too far in proposing it as a replacement for Hodgkin-Huxley, but we shouldn't throw out the baby with the bathwater.

 

[Pythagorean]

I've never heard of this before, but this is really interesting idea and at the surface sounds like it could be an accurate perspective, distinct from HH. HH model is generally a point or patch model of a "spherical cow" and takes certain simplifications for granted in trying to fit a spatially extended bag of electrochemical fluids to a point circuit.

I agree with the general sentiment, though. This could be useful for hybrid models that consider second messenger concentrations and interactions, but it also seems like you could run into a lot of parameter fitting problems here that would be headache when HH circuit-like models will work (for example, network level questions). Just depends on the question you're asking and how much happiness and time you're willing to sacrifice for playing whack a mole with parameters that you can barely measure experimentally.

 

[atyy]

https://en.wikipedia.org/wiki/Soliton_model_in_neuroscience

https://www.nature.com/articles/ncomms7697
https://www.theguardian.com/science/neurophilosophy/2015/may/01/action-waves-in-the-brain

The El Hady and Machta model is not the soliton model. They write "Our model assumes that, since these displacements are relatively small, we can assume that modes are in the linear response regime. This is in contrast to refs 15, 20, 34 in which mechanical nonlinearities, rather than electrical ones, are responsible for the solitonic shape of the AP."

 

[madness]

The El Hady and Machta model is not the soliton model. They write "Our model assumes that, since these displacements are relatively small, we can assume that modes are in the linear response regime. This is in contrast to refs 15, 20, 34 in which mechanical nonlinearities, rather than electrical ones, are responsible for the solitonic shape of the AP."

Well spotted. The El Hady and Machta model seems to be making substantially weaker and less controversial claims than the original soliton model.