www.neuron.yale.edu

I want to make a coupling compartment between my soma and the dendritic tree - so I can control how "coupled" these 2 entities are.

BUT actually - what would be better is if I dont even have a coupling compartment - but a coupling parameter - a coupling resistance value. This way I dont have to be concerned with the compartment dimensions etc. - I just have a single coupling parameter. I post here because I am unsure how to code this in hoc.

Mainen and Sejnowski (1996) did do something like this (although the relevant code is not in modeldb) - where I got the idea of a coupling resistance value. A quote from their paper:

"The parameter K specifies the electrical resistance (coupling) between the two compartments."

The trick Mainen Sejnowski use is in ModelDB in the code for their 1996 paper. If you connect section A to the middle of a section B then axial resistance of section B does not contribute to the coupling between the sections A and B, and you can use this to control the coupling. The trick however only works smoothly for two compartment models.

There are at least two ways to insert a resitance between two sections. One
is to 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.
The other way is to literally use a resistor, in the Linear Circuit Builder.