Spike Timing Problem

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chalspark
Posts: 17
Joined: Tue Jun 01, 2010 1:19 am

Spike Timing Problem

Post by chalspark »

Hello. Ted.

I always thank you for your answer.

I have a critical problem. My simulation conditions are below.

- Two IClamps
- Step Current(1000ms)
- IPSP Current(5ms, different delay each simulation after 2nd spike)
- One Izap Stimulation
- Sinusoidal Conductance(1.5nS, 5hz)
- full morphology neuron

run this simulation. I expect precise spike timing. But It isn't! ( cvode_active(1)).

I think that the IPSP current delay affect the precise spike timing in the simulation.

Before to change the delay time of IPSP, I confirm that possibility to change the delay time during simulation.

Simple simulation using GUI, i check it is possible!

So I try to get precise spike timing using APCount(2nd spike time).

and i try many ways to change the delay time (in mod file). But i have failed. how to change the delay time in the mod file or source during simulation.

I need to help to solve this problem.

Thank you.
ted
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Joined: Wed May 18, 2005 4:50 pm
Location: Yale University School of Medicine
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Re: Spike Timing Problem

Post by ted »

Tell me if I understand what you are trying to do: you want to run a series of simulations, where the thing that changes from one simulation to the next is the time at which the IPSP happens. Writing in pseudocode, this would be

Code: Select all

REPEAT
  set the IPSP delay to a new value
  run a simulation
  observe the time at which the second spike happens
UNTIL done
If this is correct, tell me how you are generating your IPSP. Are you using an AlphaSynapse, or are you using a NetStim with a NetCon and an ExpSyn or Exp2Syn?

If I misunderstood what you are trying to do, please let me know.
chalspark
Posts: 17
Joined: Tue Jun 01, 2010 1:19 am

Re: Spike Timing Problem

Post by chalspark »

Yes, Ted. It's very similar.

Code: Select all

set the second spike time from without IPSP stimulate simulation. ( I use IClamp for inject similar IPSP. )

 for i=0:windows
  set IPSP.del = second spike time + ( i * (Inter Spike Inter/windows))
  set IPSP.amp and IPSP.dur

  run a simulation

  observe the third spike
 end
this is previous simulation. In this simulation, I found that second spike time isn't fixed!

this figure are shown second spike times.
Image

So, I want to below

Code: Select all

set the temporary delay (IPSP.del = 9999ms) ( I use IClamp for inject similar IPSP. )

 for i=0:windows
  set IPSP.del = temporary delay
  set IPSP.amp and IPSP.dur

  run a simulation
  (during simulation, get the second spike time and set the IPSP.del = second spike time + ( i * (Inter Spike Inter/windows)) )

  observe the third spike time
 end
I failed set the IPSP.del during simulation in the hoc file or mod file. But i confirmed it is possible to change the IClampe delay time during simulation in the point process GUI menu.
ted
Site Admin
Posts: 5810
Joined: Wed May 18, 2005 4:50 pm
Location: Yale University School of Medicine
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Re: Spike Timing Problem

Post by ted »

I'm sorry, I really don't understand what you're talking about. Maybe someone else can help.
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