Multicomp model, ECS, pumps and strange concentrations
I was checking my RxD code, after implementing it into a multi compartmental model and something very odd came up.
I have a substance, produced by a few dendrites and, trough pumps (the same used in the RxD examples) diffused into the ECS.
If I cancel the code responsible for the generation of the substance, there is still a build up of it in the ECS and inside the sections but only when the pump mechanism is active.
If the pump is commented in the code, than the internal side and the ECS have a zero concentration, as they should be.
It is like the pump is generating the substance.
I discovered that this happens only when I'm using my 300 sections multi compartmental model since everything worked fine with a two single section models.
After some more tinkering with it.
Reducing the model to just 3 sections, soma - dend0 - dend00 (all attached in series) solved the issue.
Instead the issue reappeared with 5 sections in an Y shape like this -> Soma (first branch) dend0-dend00 and (second branch) dend1-dend11.
The two branches share the same origin point but, even placed one at 0 and the other at 0.5 does not resolve the issue.
(NEURON 7.8 compiled 4 days ago and python 3.6.9)