Measuring total membrane current in multicompartment model
Posted: Wed Jan 04, 2012 8:52 am
Dear all,
For a demonstration I want to show the attenuation of a tonic currents at some specific locations in the dendrites to the soma.
My plan of action is
- insert Iclamp at a specific location of the dendrites (for example 100 microm) and insert a long step of 10 pA
- measure currents at the soma (as in wetlab experiment with a second voltage clamp electrode).
I have a problem with the second step. How is the total membrane current defined in NEURON. I can find the individual currents (i.e. i_na) but I am not sure if I should add them all up. An earlier post pointed out that the non-specific currents are not taking into account with this method. This post suggested to add an extracellular matrix to the model and take the current flowing through this segment.
I am not familiar with extracellular mechanism.
- How do you define this mechanism for a model that consists of a detailed anatomical model?
- the current of this extracellular mechanism is still defined in xxx A/mm2 and I have to multiply this with the area to get the total current. But what is area in a multi-compartment model?
Any help is highly appreciated
For a demonstration I want to show the attenuation of a tonic currents at some specific locations in the dendrites to the soma.
My plan of action is
- insert Iclamp at a specific location of the dendrites (for example 100 microm) and insert a long step of 10 pA
- measure currents at the soma (as in wetlab experiment with a second voltage clamp electrode).
I have a problem with the second step. How is the total membrane current defined in NEURON. I can find the individual currents (i.e. i_na) but I am not sure if I should add them all up. An earlier post pointed out that the non-specific currents are not taking into account with this method. This post suggested to add an extracellular matrix to the model and take the current flowing through this segment.
I am not familiar with extracellular mechanism.
- How do you define this mechanism for a model that consists of a detailed anatomical model?
- the current of this extracellular mechanism is still defined in xxx A/mm2 and I have to multiply this with the area to get the total current. But what is area in a multi-compartment model?
Any help is highly appreciated