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AlphaSynapse vs Exp2Syn
Posted: Fri Jul 29, 2011 12:15 pm
by rllin
These two should be interchangeable code wise right? Besides AlphaSynapse having only one tau and not taking NetCon's weight for equation use, they should be the same right? They can both be connected to sources with NetCons?
Re: AlphaSynapse vs Exp2Syn
Posted: Fri Jul 29, 2011 12:56 pm
by ted
ExpSyn and Exp2Syn are driven by events. AlphaSynapse is not--it produces a single conductance transient at a time specified by its onset parameter.
Re: AlphaSynapse vs Exp2Syn
Posted: Fri Jul 29, 2011 3:01 pm
by rllin
Ah, thank you. I just reread and found that they are both also alpha functions so that's good too.
Re: AlphaSynapse vs Exp2Syn
Posted: Tue Aug 02, 2011 2:18 pm
by rllin
G = weight * factor * (exp(-t/tau2) - exp(-t/tau1))
This is the equation given for Exp2Syn.
If tau2 is close to tau1 this has the property that the maximum value is weight and occurs at t = tau1
When tau1 is close to tau2, shouldn't G approach 0? Am I missing something here? Thanks!
Re: AlphaSynapse vs Exp2Syn
Posted: Tue Aug 02, 2011 4:48 pm
by ted
factor
Re: AlphaSynapse vs Exp2Syn
Posted: Wed Aug 03, 2011 8:51 am
by rllin
Your (exp(-t/tau2) - exp(-t/tau1)) term would still be 0, no?
Re: AlphaSynapse vs Exp2Syn
Posted: Wed Aug 03, 2011 9:45 am
by ted
Read the source code and discover that the condition
tau1 = tau2
is trapped by a conditional statement that forces a nonzero difference between them. This happens before the value of factor is calculated.
Re: AlphaSynapse vs Exp2Syn
Posted: Wed Aug 03, 2011 11:14 am
by rllin
Ah, thanks!
Re: AlphaSynapse vs Exp2Syn
Posted: Wed Aug 03, 2011 2:35 pm
by rllin
Also, AlphaSynapse has
the property that the maximum value is gmax and occurs at
t = delay + tau.
What is this delay? Thanks!
Re: AlphaSynapse vs Exp2Syn
Posted: Thu Aug 04, 2011 10:31 am
by ted
A typographical error. The revised documentation will read
the maximum value is gmax and occurs at
t = onset + tau.
Re: AlphaSynapse vs Exp2Syn
Posted: Thu Aug 04, 2011 12:00 pm
by rllin
Ah, thank you. And just as a note to people that might have the same question, this arrives simply by finding the peak through setting the time derivative to zero.