about the netcon

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yj232

about the netcon

Post by yj232 » Mon Jun 27, 2011 10:47 am

I've got a network with a motor neuron as the output and several interneurons.
I have a simple question that when I connect several interneurons to a single synapse, how's the input? Do all the input add together when I connect them or I need to do it by coding?
Last edited by yj232 on Mon Jun 27, 2011 11:56 am, edited 1 time in total.

ted
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Re: about the netcon

Post by ted » Mon Jun 27, 2011 11:14 am

ExpSyn and Exp2Syn handle multiple input streams correctly. That is, events from different spike sources produce conductance changes that add linearly.

yj232

Re: about the netcon

Post by yj232 » Mon Jun 27, 2011 11:57 am

Thanks for that.
And is there anyway to plot the voltage of ExpSyn or Exp2Syn?

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Re: about the netcon

Post by ted » Mon Jun 27, 2011 1:26 pm

yj232 wrote:is there anyway to plot the voltage of ExpSyn or Exp2Syn?
Voltage? These mechanisms have a constant reversal potential, value specified by the user. Maybe you mean "membrane potential at the site where the synapse is attached"? If yes, you already know how. The hoc name of the membrane potential will be
sectionname.v(range)
where
sectionname is the name of the section to which the synapse is attached
range is the location on the section where the synapse is attached.
So
objref syn
dend[25] syn = new ExpSyn(0.7)
means that the ExpSyn is attached to dend[25] at a point that is 70% of the distance from dend[25]'s 0 end, and the membrane potential at that location is dend[25].v(0.7). If you want to plot that in a Voltage axis graph, use the graph's "Plot what" to add dend[25].v(0.7) to the graph's plotlist. If you don't know about "Plot what", see "Q: How do I plot something other than membrane potential?" in the FAQ list http://www.neuron.yale.edu/neuron/faq

yj232

Re: about the netcon

Post by yj232 » Mon Jun 27, 2011 2:16 pm

thanks for that. However, besides the voltage, how can I plot some other variables? like the conductance of the synapse and current, or other parameters like the state variables? Is there anyway to explicitly plot those parameters inside the mod file?

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Re: about the netcon

Post by ted » Mon Jun 27, 2011 2:21 pm

yj232 wrote:besides the voltage, how can I plot some other variables?
Read the FAQ list item I pointed you to. Why do you think that item has the title
"Q: How do I plot something other than membrane potential?"
??
Is there anyway to explicitly plot those parameters inside the mod file?
No. That's not what mod files are for.

yj232

Re: about the netcon

Post by yj232 » Mon Jun 27, 2011 4:52 pm

Yes I've read that. That only works for all the parameters shown in GUI. But how about other parameters which are not shown there?
How is it supposed to check if a parameter is working fine in mod file? For example, how to check the conductance of a synapse? I know I can use print command to print the values out, is this the only way?

Sorry I have so many questions:)

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Re: about the netcon

Post by ted » Tue Jun 28, 2011 1:35 pm

For mechanisms described by NMODL code, all STATEs are range variables and are visible from hoc. Also visible from hoc are all variables that are declared to be RANGE or GLOBAL in the NEURON block. The Graph class's "Plot what" tool is actually a "variable name browser" that shows the names of all variables that are visible from hoc. For example, suppose you have a model with an instance of the ExpSyn class called ExpSyn[0]. ExpSyn's STATE variable is g, which is the synaptic conductance, and you could use the "Plot what" tool to discover the variable ExpSyn[0].g (or you could just type
ExpSyn[0].g
at the oc> prompt and get a valid numerical result).

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