Izhikevich neurons and GJs

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shyam_u2
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Izhikevich neurons and GJs

Post by shyam_u2 »

I am trying to create a network of Izhikevich neurons (http://senselab.med.yale.edu/modeldb/sh ... zh\izh.mod) connected by Gap junctions. The neuron's voltage is vv which is quite different from the soma's voltage v in which it is inserted. But gap junctions just calculate the current from NEURON's inbuilt variable v and the current thus calculated is automatically integrated with v. May I know how to handle this issue with Izhikevich type neuron ie how do i implement gap junctions with Izhikevich type neuron ? How do I update the inbuilt variable v from the values of vv ?

Thanks in advance.
wwlytton
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Re: Izhikevich neurons and GJs

Post by wwlytton »

It would seem fairly easy to copy the voltage over from vv to v -- this would go after the SOLVE in the BREAKPOINT.

But this is less than 1/2 the problem since then will also want to get back into vv and this is not a simple copy but needs to add in to the integration. Therefore what you need is the current from the gap junctions. If you only wanted a single gap junction I would suggest incorporating the gap junction mechanism into the same POINT_PROCESS.

However I assume that you may want to connect many gap junctions to the same cell and that this code would then live mostly at the hoc/python level as setpointer? (I'm not recalling offhand how gap junctions are best done; perhaps you could also give a pointer or code for the gap junction implementation that you are trying to use).

So I'm thinking that the gap junction feeds into a nonspecific current I and that the modified Izh POINT_PROCESS will then read the I -- however I'm not sure that a POINT_PROCESS can read a current? -- that's something usually done in a membrane mechanism (SUFFIX).

NB I haven't tried any of this. Let me know how it goes.

bill
ted
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Re: Izhikevich neurons and GJs

Post by ted »

wwlytton wrote:I'm not recalling offhand how gap junctions are best done
Would use the LinearMechanism class for this. At least one example of this usage is in ModelDB; I'd guess it would be in a recent network model by Migliore.
shyam_u2
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Re: Izhikevich neurons and GJs

Post by shyam_u2 »

NB I haven't tried any of this. Let me know how it goes.
Yes i will post it here when I m done.. Thanks..
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