Myelin modeling

[OronKotler]

Hi all this is my code for myelin double circuit model, this is the paranode extntion:

h.paranode[1].insert('extracellular')
h.paranode[1].xraxial[0]=Rpn1
h.paranode[1].xraxial[1]=Rpn1
newgm=np.divide(gm,(np.array(h.paranode[1].L)))
h.paranode[1].xg[0]=2*gm/(np.array(h.paranode[0].L))
h.paranode[1].xg[1]=2*gm/(np.array(h.paranode[0].L))
h.paranode[1].xc[0]=2*cm/(np.array(h.paranode[1].L))
h.paranode[1].xc[1]=2*cm/(np.array(h.paranode[1].L))


I get don't really understand how to describe the different xg,xraxial and xc for the double circuit model, is what I write okay?
is there an example for myelin in the extracellular mechanism that I can use?
Do I need to do this for the node of the system? and if I do is there a specific Ca for the extracellular space?

[ted]

What "myelin double circuit model" are you referring to?

With regard to models of spike propagation in myelinated axons, many authors have published such models. Most of them use very simple representations of the electrical effects of the myelin sheath. Whether one is better than another for any particular application depends entirely on the research question that is being addressed. More complexity does not necessarily mean better.

[OronKotler]

Hi Ted,
thanks for replying to my post.

I am trying to model the double cable circuit used by Wårdell et al 2019 with the extracellular mechanism offered by NEURON. I am wondering what is the best approach for understanding what parameters I need to us for the xraxial,xg,xc in order to simulate this circut. what are the governing equations for these parameters?

Thanks again for your help,

Oron

[ted]

I am trying to model the double cable circuit used by Wårdell et al 2019

I have no suggestions, having never seen the paper. Presumably the authors describe their methodology sufficiently clearly that correspondences between their parameters and those of NEURON's extracellular "mechanism" are apparent. extracellular is described in some detail in the Programmer's Reference--see https://neuronsimulator.github.io/nrn/h ... ml#index-5
or just look in the alphabetical index (see link at https://neuronsimulator.github.io/nrn/python/index.html) for the keyword
extracellular