EasyML handling external stimulus current

Question

I have been trying to implement the ToR-ORd model and have run into a situation where the external stimulus current affects the ionic concentrations. How can I import the stimulus current into EasyML? (My intuition is using .external(), but could not find the GlobalData_t variables.) 

On a related note, when looking through opencarp.prm, the adj_stim_ions flag seems to control this behavior, but could not find additional documentation on it.

Any pointers to ionic models that already do this are much appreciated!

Answer 1

The accounting of the stimulus current is only supported on the single cell level. The bench options --stim-assign, --stim-species and --stim-ratios are used to control this.

On the tissue level, this is not supported currently (the openCARP.prm option you mentioned is commented by a preprocessor macro).

Code contributions to support this function on the tissue level are welcome. 

Comments

Interesting to hear...I am thinking about how the stimulus current support should be implemented. Within openCARP, how is the stimulus current accounted for when calculating dV? Is it necessary for the stimulus current to be added to Iion within the .model file?

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You can see how this is handled on the single cell level in the bench code:
https://git.opencarp.org/openCARP/openCARP/-/blob/master/physics/limpet/src/bench.cc#L543

It makes use of the transmem_stim_species method of the MultiIonIF class:
https://git.opencarp.org/openCARP/openCARP/-/blob/master/physics/limpet/src/MULTI_ION_IF.cc#L1619

No need to explicitly represent it in the .model file as far as I see as long as Ca, Na, K or Cl are the ions being used.