Voltage clamping different compartments at different times

[Bill Connelly]

Hi,

Firstly, I apologise if this question is answered elsewhere. If I had a modelled a neuron with two dendrites, how would I use the SEClamp point process to apply a voltage clamp family to a point on one dendrite, and then later essentially turn that voltage clamp off, and apply the same voltage clamp family to a point on the other dendrite?

Using IClamp, this would simply be a matter of setting the second IClamp to have a del such that it would start after the first IClamp process had finished.

It is possible to do this or do I need to run two separate simulations?

Thanks.

[ted]

Point processes have a method called loc() that can be used to specify their placement
under program control.

In the real world, one would proceed exactly as you describe:
patch clamp one location, gather some data, move the patch to another site, wait for
the cell to recover, then get some more data.
But in computational modeling, it's more efficient to run a series of short simulations,
collecting data during each run, then present the collected results afterward.

One of the exercises we have done in the hands-on NEURON course involves marching
an AlphaSynapse along the length of a "dendrite" section, recording the peak amplitude
of the elicited epsp as observed at the soma, and plotting the amplitude as a function of
distance from the synapse to the soma. The exercise is "Model Control: Simulation
Families" http://www.neuron.yale.edu/course/family.html . If you download the complete
zip file for the course
http://www.neuron.yale.edu/neuron/sdsc2003/course.zip
you will find the exercise and its solution files in course/family --
nrngui init_solution.hoc
(or double click on init_solutuion.hoc if you are using MSWin) will load and run the solution.
You can mine the code in putsyn.hoc and profile.hoc to do what you want.