gap junction and coupled resistance

[thats_karlo]

Hello,

I am wondering, can we use gap junction insted of coupled resistance between to section?

for example, consider to section A and B with a couple resistsnce

(A)-/\/\/\/\/\/\-(B)

1-Dose the following code, is a correct way to represent the above figure?
dose it need some correction?

Code: Select all

create A, B
forall nseg=1
A{\\geometry +biophysics}
B{\\geometry +biophysics}

objref RG
RG= new gap()

A RG[0].loc(0.9999)
B RG[1].loc(0.0001)
setpointer RG[0].vgap, B.v(0.0001)
setpointer RG[1].vgap, A.v(0.9999)

RG.r=0.1

2-Is ti right: if A{r1=ri(0.9)} ,B{r2=ri(0.1)}, then

axial resistance between A, B =r1+r2+RG.r

3- can we make a cell with two compartment, AND a copuling resistance in GUI tool\cell builder?


Yours,


karlo

[ted]

For an example of how to connect cells with gap junctions, see
Migliore M, Hines ML, Shepherd GM (2005)
The role of distal dendritic gap junctions in synchronization of mitral cell axonal output.
J Comp Neurosci 18:151-161

Working code is available from ModelDB
http://senselab.med.yale.edu/modeldb/Sh ... odel=43039

[thats_karlo]

Dear Ted,

I looked at the paper and files. It is very nice model.Thanks for this reference. But actually i don't want to model gap junction. I'm wondering is it possible to use gap junction resistance as a coupled resistance between two compartment?

By the way, in one post you suggested:

....put a third section in between the other two, being careful to make the
dimensions and Ra of the intermediate section such that the desired
resistance is obtained; be sure to set that section's cm to 1e-9.

It seems very easy way to create a coupled resistance between to compartment. in this case what is the exact formula for resistance of The third compartment, as you described above? I gusse it should be, something like: R=Ra*L/pi/diam^2

Is it true?

[ted]

resistance = Ra * path length / cross-sectional area
= Ra * L * 4 / (PI * diam^2)
Don't forget units--Ra is in ohm cm, L and diam in um.

[thats_karlo]

Thank you so much for help!