Axon: Soliton?

[bernard]

Hi All,

Does an axon carry its AP as a soliton?


http://www.somasimple.com/flash_anims/soliton_01.swf

Here we are seeing the Action Potential that is a virtual image coming from activation of ions channnels. It is a part of an axon and its shape is quite regular.

We may consider that the wave is self propagated (that is true) but many researchers seems in concordence on one point the soliton theory fails with dendrites sites. Why?

1/ the AP does not follow the solitons rules?
3/ the AP isn't a soliton but a soliton like?

[bernard]

Here is two "real" solitons waves colliding. In fact they cross themselves and continue their routes. The important thing to note is that when they met, their energies are for a moment, added. The amplitude is then normally quite the sum of the 2 components.

The single value is yet different than a possible application to axon. AP is dependent of its size and myelinization.

http://www.somasimple.com/flash_anims/soliton_02.swf

[bernard]

Tried to make the previous example clearer?

http://www.somasimple.com/flash_anims/soliton_03.swf

[nari]

Bernard

Looks great!!

A nice dune...



nari

[bernard]

In a normal axon if it was possible to encounter two opposite APs then it will look like this =>

http://www.somasimple.com/flash_anims/soliton_04.swf

Many experiments had been tried and show a similar result. APs are not solitons because the underlying process that create them is different.

[fapt]

In a normal axon if it was possible to encounter two opposite APs then it will look like this =>

http://www.somasimple.com/flash_anims/soliton_04.swf

Many experiments had been tried and show a similar result. APs are not solitons because the underlying process that create them is different.

hi bernard....
i think at the middle, the Action potential should be the nearly twice times of the orange and blue action potential.
Because they all are postivesingle...
And then decline to zero.... :roll:

[bernard]

Lin,

just impossible! :wink:

I'm convinced that they do not met! :idea:

[bernard]

Hi SomaSimplers,

I contacted Chris DAVIA
http://www.psy.cmu.edu:16080/~davia/mbc/ (http://www.psy.cmu.edu:16080/%7Edavia/mbc/)

And we have already exhanged some words. Hope he will give his opinion there?

ps: look at this previous post
http://www.somasimple.com/forums3/viewtopic.php?t=664

[EricM]

Bernard, I'm trying to follow your reasoning. For example, is this what happens in the 'double crush syndrome?" Only the AP originating at the more proximal site of injury arrives at the DRG? The more distal one being cancelled by the distally travelling AP from the proximal site? I hope that makes sense.

eric

[EricM]

If at a molecular level AP's are not true soliton's, can the behaviour of the nervous system be viewed through a different lens and seen as a metaphorical soliton?

eric

[EricM]

Good work Bernard! Thank-you.

Eric

[bernard]

If the facts don't fit the theory, change the facts.

Albert was of course "seriously" kidding! :lol: But since 1900 Science is lost with neuron! :roll:

Just change the facts (and theories)!

[bernard]

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15156147

Nat Neurosci. 2004 Jun;7(6):621-7. Epub 2004 May 23.

Computational subunits in thin dendrites of pyramidal cells.

Polsky A, Mel BW, Schiller J.

Department of Physiology, Technion Medical School, Bat-Galim, Haifa 31096, Israel.

The thin basal and oblique dendrites of cortical pyramidal neurons receive most of the synaptic inputs from other cells, but their integrative properties remain uncertain. Previous studies have most often reported global linear or sublinear summation. An alternative view, supported by biophysical modeling studies, holds that thin dendrites provide a layer of independent computational 'subunits' that sigmoidally modulate their inputs prior to global summation. To distinguish these possibilities, we combined confocal imaging and dual-site focal synaptic stimulation of identified thin dendrites in rat neocortical pyramidal neurons. We found that nearby inputs on the same branch summed sigmoidally, whereas widely separated inputs or inputs to different branches summed linearly. This strong spatial compartmentalization effect is incompatible with a global summation rule and provides the first experimental support for a two-layer 'neural network' model of pyramidal neuron thin-branch integration. Our findings could have important implications for the computing and memory-related functions of cortical tissue.

PMID: 15156147 [PubMed - indexed for MEDLINE]

[bernard]

Well guys,

I'm busy at the moment and writing a paper for publication about my findings.
Neuron uses a super solitonic solution! :wink: