could you give me an example!

[antonio]

hi everybody!

i'm a bigenner in NEEURON. and really i learn alot from quanstions and answers. special thank's to admin!

i want to ask a quastion that befor me somebody else also were looking for it's answer.
my question in brief:

clould you give me a example of how do you hyperpolarized/ depolarized e.g, a soma (change the membrane potential) and at the same time you inject current?

i'm sure it will be a combination of voltage clamp and current clamp, but i didn't get from previous answer, how do you manage it!!!


thank's in advance,

antonio

[Raj]

Hi Antonio,

However usefull this forum might be you will probably learn more from a well structured text, this is available in Ted's book:
http://www.neuron.yale.edu/ftp/ted/book/

Coming more directly to your question, it is in general not a good idea to combine a current and a voltage clamp protocol on the same compartment, the only thing that will happen is that the voltage clamp will generate more current to compensate for the injected current. This will leave the membrane potential unchanged, which is the purpose of a voltage clamp protocol.

You might combine them in a sensible way, if you want to assess how much of the current injected in the dendrites will reach the soma, just attach a IClamp object to the dendrites and a VClamp or SEClamp to the soma and monitor the current generated by the VClamp or SEClamp mechanism in response to different amounts of current injected into the dendrites, or different injection positions on the dendrites.

Raj

[ted]

clould you give me a example of how do you hyperpolarized/ depolarized e.g, a soma (change the membrane potential) and at the same time you inject current?

i'm sure it will be a combination of voltage clamp and current clamp

Think like an experimentalist. Or ask one. The answer is: inject a steady hyperpolarizing
current with a current clamp. Wait for the cell to settle to its new resting level. After it
settles, inject a depolarizing current with a second current clamp.

So you're right, it is a combination of voltage and current clamps. Use 0 voltage clamps
and 2 current clamps.