: STDP by Hines, changed to dual exponential (BPG 6-1-09)
: Modified by BPG 13-12-08
: Limited weights: max weight is wmax and min weight is wmin
: (initial weight is specified by netconn - usually set to wmin)
: Rhythmic GABAB suppresses conductance and promotes plasticity.
: When GABAB is low, conductance is high and plasticity is off.
NEURON {
POINT_PROCESS STDPE2
RANGE tau1, tau2, e, i, d, p, dtau, ptau, thresh, wmax, wmin
RANGE g, gbdel, gblen, gbint, gscale, factor,dM,dV,B,C
NONSPECIFIC_CURRENT i
}
UNITS {
(nA) = (nanoamp)
(mV) = (millivolt)
(uS) = (microsiemens)
}
PARAMETER {
tau1=.1 (ms) <1e-9,1e9>
tau2 = 10 (ms) <1e-9,1e9>
e = 0 (mV)
pi=3.14159
wmax = 0.0015 (uS)
:wmax = 0.005 (uS)
wmin = 0.0005 (uS) : not used - use netconn weight instead (BPG)
d = 8 : depression factor (multiplicative to prevent < 0)
p = 1.2 : potentiation factor (additive, non-saturating)
dM = -22 (ms)
dV= 5 (ms)
ptau = 10 (ms) : Nishiyama2000
:thresh = -20 (mV) : postsynaptic voltage threshold
thresh = -55 (mV) : postsynaptic voltage threshold
gbdel = 50 (ms) <1e-9,1e9> : initial GABAB off interval (ms)
gbint = 125 (ms) <1e-9,1e9> : GABAB off interval (ms)
gblen = 125 (ms) <1e-9,1e9> : GABAB on length (ms)
gscale = 0.4 : relative suppression by GABAB
}
ASSIGNED {
v (mV)
i (nA)
tpost (ms)
on
g (uS)
gs
factor
}
STATE {
C (uS)
B (uS)
}
INITIAL {
LOCAL tp
if (tau1/tau2 > .9999) {
tau1 = .9999*tau2
}
C = 0
B = 0
tp = (tau1*tau2)/(tau2 - tau1) * log(tau2/tau1)
factor = -exp(-tp/tau1) + exp(-tp/tau2)
factor = 1/factor
gs=1
on=0 : initially not plastic
tpost = -1e9
net_send(0, 1)
net_send(gbdel, 3) : initial GABAB off period
}
BREAKPOINT {
SOLVE state METHOD cnexp
g = B - C
i = g*gs*(v - e)
}
DERIVATIVE state {
C' = -C/tau1
B' = -B/tau2
}
NET_RECEIVE(w (uS), A, tpre (ms) ) {
INITIAL { A = 0 tpre = -1e9 }
if (flag == 0) { : presynaptic spike (after last post so depress)
: printf("entry flag=%g t=%g w=%g A=%g tpre=%g tpost=%g\n", flag, t, w, A, tpre, tpost)
: g = g + w + A : only for single exp (BPG)
C = C + (w + A)*factor
B = B + (w + A)*factor
:printf(" B %f\t C %f\t w %f\n",B, C, w)
tpre = t
if (on == 1) {
A = A * (1-(d*exp(-((tpost-t)-dM)^2/(2*dV*dV))) /(sqrt(2*pi)*dV))
}
}else if (flag == 2 && on == 1) { : postsynaptic spike
: printf("entry flag=%g t=%g tpost=%g\n", flag, t, tpost)
tpost = t
FOR_NETCONS(w1, A1, tp) { : also can hide NET_RECEIVE args
:printf("entry FOR_NETCONS w1=%g A1=%g tp=%g t=%g\n", w1, A1, tp, t)
A1 = A1 + (wmax-w1-A1)*p*exp((tp - t)/ptau)
}
} else if (flag == 1) { : flag == 1 from INITIAL block
: printf("entry flag=%g t=%g\n", flag, t)
WATCH (v > thresh) 2
}
else if (flag == 3) { : plasticity control
if (on == 0) { : start plasticity
on = 1
gs = gscale
net_send(gblen, 3)
}
else { : end burst
on = 0
gs = 1
net_send(gbint, 3)
}
}
}