questions about myelinated axon model

[Chen Yi]

Dear Ted and all,
The code below is from McIntyre's model(2002) and I add some comments to make it easier to read.

Code: Select all

for i=0, paranodes1-1 {
		MYSA[i]{
			nseg=1
			diam=fiberD
			L=paralength1
			Ra=rhoa*(1/(paraD1/fiberD)^2)/10000
			cm=2*paraD1/fiberD
			insert pas
			g_pas=0.001*paraD1/fiberD                                          
			e_pas=v_init
			insert extracellular xraxial=Rpn1 xg=mygm/(nl*2) xc=mycm/(nl*2)  //nl:number of myelin lemella, mygm:myelin conductance 
			}

Now I have 2 puzzles:
1.Why 'xg=mygm/(nl*2)'? As there are nl layers of transverse resistive in series. I think it should be mygm/nl.
2.What does 'xraxial' means and what's the unit of it?
Please tell me.
Thank you!

[ted]

1.Why 'xg=mygm/(nl*2)'? As there are nl layers of transverse resistive in series. I think it should be mygm/nl.

Good question. If you don't find the answer in the model's "readme" file, source code comments, or the paper itself, then ask the model implementer or author.

2.What does 'xraxial' means and what's the unit of it?

Defined in the Programmer's Reference documentation of the extracellular mechanism--see http://www.neuron.yale.edu/neuron/stati ... racellular