sinusoidal current injection as a Transmembrane current

[SarahJansky]

Hi All

I have open a topic like this but I have understood that I need another thing,

I am simulating a single compartment HH model in MATLAB, and use there a sinusoidal current injection like this;

Iinject=A*sin(wt);
I_total=Iinject-(INa+IK+etc...);

I think this injection current is a transmembrane current injection to soma? what do you think about it?

There is a subject in the forum (https://www.neuron.yale.edu/phpBB2/viewtopic.php?t=897)
but it says it is a ELECTRODE current? I use this but it didnt give the same results in my MATLAB program.

Do you think How can I do this transmembrane current injection in NEURON ?

Regards

[ted]

I think this injection current is a transmembrane current injection to soma?

No because it is not generated by transmembrane ion fluxes. It is imposed by "injection"
through an electrode.

There is a subject in the forum (https://www.neuron.yale.edu/phpBB2/viewtopic.php?t=897)
but it says it is a ELECTRODE current?

ELECTRODE_CURRENT i
in the NEURON block
is used to tell NMODL that i is a current that is injected into the cell via an electrode.
Therefore

1. Positive values of i will depolarize the cell. This differs from currents generated by ion
channel, leak, ion exchange, or pump mechanisms, which generate transmembrane
currents, because negative transmembrane currents depolarize the cell.

AND

2. i is a current that is injected directly into the cell, so if the extracellular mechanism is
present, i will affect vext even if the model has only a single compartment, because the
"return path" for i must pass through the extracellular mecanism's layers. This differs from
ion channel, leak, ion exchange, or pump mechanisms, which generate transmembrane
currents that do not have to pass through the extracellular mechanism's layers and will not
affect vext of a single compartment model.

I use this

Which "this" did you use? Kelvin's code with my suggested modifications--if done properly--
should work correctly.

but it didnt give the same results in my MATLAB program

If the difference is significant and not attributable to different integration methods or
roundoff error, then either your MATLAB program, or your NEURON program--or both of
them--is incorrect. If there is an error, it may be in specification of model properties,
specification of the stimulus, or initialization of the simulation.