Simulating sensing electrodes

Question

Hello,

Has anyone tried to create and simulate a spherical sensing electrode on top of a 3D/2D substrate?

I'm trying to create a simple 1-mm^3 spherical electrode so I can sense unipolar electrograms from a substrate. What I've tried so far is as follows:

1) Recreating the extracellular potentials tutorial to fit my simulations. Although this gives me an extracellular potential, it is derived from a single point at the bath/tissue border, this does not replicate electrode conductivities and the averaging effect on the signal due to the electrode surface.

2) I defined a spherical region on top of my substrate to represent my electrode and defined isotropic conductivities to simulate an Ag/AgCl electrode. However, openCARP automatically assigns LuoRudy94 on the spherical region and produces its own transmembrane potentials when executed.

Any tips for creating unipolar electrodes to sense extracellular potentials in openCARP? Is this a matter of post-processing phie?

Thanks in advance!

Karl

Answer 1

The bath and the electrode should not be part of your intracellular domain. You can find instructions how to split your domain in intra+extra and extra-only in this example https://opencarp.org/documentation/examples/02_ep_tissue/07_extracellular#exp-em-ti-ecg-03

Like this, you can run pseudo-bidomain or bidomain simulations with the electrode included in the extracellular-only part of the mesh.