### Question about edge of cylinder and axial resistance

Posted:

**Tue Apr 28, 2015 4:49 am**Hello,

I am trying to understand how Neuron is building the section and I am not sure I understand correctly. Especially I have problem understanding the edges of the cylinders.

Questions:

1. there is no membrane resistance in the edges of the cylinders? If I want to calculate the total membrane resistance of a cylinder I need to calculate the surface of the cylinder without the cylinder ends surface? and not

2. When I dived the cylinder to compartments what happens in the edges ( when the cylinder is isolated and not connected to other cylinders)

For Example:

If I build the following cylinder

3. This will be the equivalent circuit?

( The values are Ra-end =106103295.39459689 , Ra-middle = 212206590.78919378

Rm = 1909859317.1027443

Cm = 5.235987755982987e-12

)

4. the edges are not connected to nothing?

If for example I build 2 cylinders and connect them with Gap Junctions, as the following:
5. This will be the corresponding circuit?

6. Where will the gap junction be connected if I do ?

Thank You.

I am trying to understand how Neuron is building the section and I am not sure I understand correctly. Especially I have problem understanding the edges of the cylinders.

Questions:

1. there is no membrane resistance in the edges of the cylinders? If I want to calculate the total membrane resistance of a cylinder I need to calculate the surface of the cylinder without the cylinder ends surface?

Code: Select all

`2*pi *(diam/2)*L`

Code: Select all

`2*pi *(diam/2)*L + 2*pi*(diam/2)ˆ2`

2. When I dived the cylinder to compartments what happens in the edges ( when the cylinder is isolated and not connected to other cylinders)

For Example:

If I build the following cylinder

Code: Select all

```
create soma
diam = 1 //um
L = 500 //um
Ra = 100
cm =1
insert pas
g_pas = 1/10000
e_pas = 0
nseg = 3
```

3. This will be the equivalent circuit?

( The values are Ra-end =106103295.39459689 , Ra-middle = 212206590.78919378

Rm = 1909859317.1027443

Cm = 5.235987755982987e-12

)

4. the edges are not connected to nothing?

If for example I build 2 cylinders and connect them with Gap Junctions, as the following:

Code: Select all

```
create soma
diam = 1 //um
L = 500 //um
Ra = 100
cm =1
insert pas
g_pas = 1/10000
e_pas = 0
nseg = 3
create soma1
diam = 1 //um
L = 500 //um
Ra = 100
cm =1
insert pas
g_pas = 1/10000
e_pas = 0
nseg = 3
objref GJ1
objref GJ2
GJ1 = new Gap(0.5)
soma { GJ1.loc(0.9999)}
GJ2 = new Gap(0.5)
soma1 { GJ2.loc(0.9999)}
setpointer GJ1.vgap, soma1.v(0.9999)
setpointer GJ2.vgap, soma.v(0.9999)
```

6. Where will the gap junction be connected if I do ?

Code: Select all

```
...
objref GJ2
GJ1 = new Gap(0.5)
soma { GJ1.loc(1)}
GJ2 = new Gap(0.5)
soma1 { GJ2.loc(1)}
setpointer GJ1.vgap, soma1.v(1)
setpointer GJ2.vgap, soma.v(1)
```

Thank You.