COMMENT
Integrate and Fire Unit
Rather than control v, when threshold is reached a strong
current (gON) is switched on for spikedur, the amplitude of the
spike is determined by the equilibrium potential of gON (eON).
At offset gOFF is turned on for one time step. The repolarizing
potential is determined by the equilibrim potential of gOFF (eOFF).
I think I did this because I could not figure out how
to control v (outside of fadvance), which is transparently updated.
The AHP consists of an instantaneous current gAHP with time
constant tau
REBOUND: to simulate rebound I made the Eleak increase (thus increasing)
resting membrane potential) whenever the cell is hyperpolarized.
ENDCOMMENT
UNITS {
(mV) = (millivolt)
(mA) = (milliamp)
}
INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}
NEURON {
SUFFIX ExIAF
NONSPECIFIC_CURRENT i
GLOBAL spikedur, refact, tauAHP, eAHP, gAHPbar, ThrConst
RANGE Thr, lastspike
RANGE gPAS, ePAS, gAHP, AHPon, gON, gOFF, eON, eOFF
:FOR PLASTICITY
RANGE SetCa, AvgCa, Ca, tauDCCa, Gain
RANGE ScaleFactor, Induction
GLOBAL SCALE, GainConst
GLOBAL tstop, terror
RANGE B :Mg Block for postsynaptic cell
}
PARAMETER {
v
i (mA/cm2)
gPAS = 0.0001 :*0.001 (mho/cm2)
ePAS = 60 : (mV)
ePASconst = 60
ThrConst = 45 :*40 Somehow, this is the true Threshold!!
Thr = 45 :*40
spikedur = 0.6 :*1 (ms)
refact = 3 :*2.0 (ms)
gONconst = 1 : (mho/cm2)
gOFFconst = 1 : (mho/cm2)
eON = 40 : (mV)
eOFF = 53 : *60 (mV)
tauAHP = 0.2 : *0.1 (/ms) : 1/tau = actual time constant of gAHP decay
gAHPbar = 0.00035 : *0.00005 (mho/cm2) : peak of AHP current. ACtually I think the units are S/cm2
eAHP = 90 : (mv)
SetCa = 1
tauDCCa = 10 : in # of trials
SCALE = 0 : USED TO GATE SCALING PLASTICITY
GainConst = 0.1 : Learning Rate
tstop
terror
}
ASSIGNED {
lastspike
gAHP (mho/cm2)
AHPon : turns AHP on after spike ends
gON (mho/cm2)
gOFF (mho/cm2)
Ca
AvgCa
ScaleFactor
Induction
Gain
B
}
INITIAL {
ePAS = ePASconst
gAHP = 0
AHPon = 9e4
gON = 0
gOFF = 0
terror = dt/10
lastspike = 9e4
Ca=0
Induction = 0
}
BREAKPOINT {
SOLVE update
i = gPAS*(vePAS) + gAHP*(veAHP)+gON*(veON)+gOFF*(veOFF)
B=mgblock(v)
}
PROCEDURE update() { LOCAL q, dv
: TURN ON AND OFF gON and gOFF to generate ACTION POTENTIAL
gON = 0
gOFF = 0
q = (tlastspike)  spikedur
if (q>refact) { : refactory period over?
if (v>Thr) { : threshod reached?
gON = gONconst : turn spike current on
lastspike = t
Ca = Ca+1
}
}
else if ( q < 0 ) { : spike still on
gON=gONconst
}
else if (v > 0) { : turn spike off
gOFF = gOFFconst
gAHP = gAHP + gAHPbar
AHPon = t
}
gAHP = gAHP  gAHP*tauAHP*dt
::: INDUCTION :::
::: HACK SO THAT INDUCTION IS RUN ON THE SECOND TO LAST TIMESTEP
if ( t>(tstop(2*dt)+terror) ) {
: Induction==0(means that it has not got to INDUCTION yet
: SCALE!=0 (means you are in a plastic mode)
if (Induction==0) {
SOLVE INDUCTION
}
}
::: END INDUCTION :::
} ::: END UPDATE :::
PROCEDURE INDUCTION() {
::: INDUCTION :::
AvgCa = AvgCa+(Ca  AvgCa)/tauDCCa
:ScaleFactor = 1+(GainConst*(SetCaAvgCa)/(SetCa+AvgCa))*SCALE
:ScaleFactor = (GainConst*(SetCaAvgCa)/(SetCa+AvgCa))*SCALE
ScaleFactor = GainConst*(SetCaAvgCa)*SCALE
::: Triggers PLASTICITY IN EPSPplas
Induction = 1
:VERBATIM
: printf("INDUCTIONExIAF t=%f Ca=%f %f\n",t,Ca,ScaleFactor);
:ENDVERBATIM
::: END INDUCTION :::
}
FUNCTION mgblock(v(mV)) {
:mgblock(100,0,50)(w/ 0.0062 = 0.9994,0.78,0.138
TABLE
FROM 140 TO 80 WITH 1000
if (v>58) {
mgblock = 1/( 1+exp( (35v)/6 ) )
:mgblock = 1/( 1+exp( (30v)/6 ) )
} else {
mgblock = 0
}
}
