How to introduce passive ionic model in one region of the mesh

Question

I have done some researches and I see that in the script ionic.py, there is a reference to a passive ionic model. I want to introduce a passive region in my tissue, so I have tried to use this function with this configuration:

model.ionic.PassiveIonicRegion(indexes,'Passive elements patch'),

where: indexes is a vector of all the indexes of region's elements and 'Passive element patch' is the name of the region.

So, in particular, my questions are:

1)Have I used the function correctly?

2)Should I introduce a new region with the command imp_region? And if so, should I have to put the model's name as 'Passive'?

3)How can I check if the region is actually passive?

Comments

In alternative, I have found also the function  model.conductivity.ConductivityRegion.passive. What is the best?

Answer 1

Ionic model and conductivity are two different properties of a region. With ionic model you control which membrane model is being chosen, with conductivity, you can set the intracellular and extracellular (or monodomain) conductivities.

A region can have an active membrane model but 0 conductivity or a passive membrane model in a region with non-zero conductivity or any other combination. What to chose depends on what you want to model.

The relevant openCARP parameters are imp_region[] and gRegion[], respectively.

If you want to use carputils, model.ionic.PassiveIonicRegion() and model.conductivity.ConductivityRegion.passive() are the respective functions. 

Indexes should hold a list of material tags instead of a list of element IDs