COMMENT
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//
// NOTICE OF COPYRIGHT AND OWNERSHIP OF SOFTWARE
//
// Copyright 2007, The University Of Pennsylvania
// School of Engineering & Applied Science.
// All rights reserved.
// For research use only; commercial use prohibited.
// Distribution without permission of Maciej T. Lazarewicz not permitted.
// mlazarew@seas.upenn.edu
//
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
ENDCOMMENT
NEURON {
POINT_PROCESS Exp2SynNMDA
RANGE tau1, tau2, tau12, tau22, e, i, i2
NONSPECIFIC_CURRENT i, i2
RANGE S, S2, Smax, gmax, total, r
GLOBAL c
}
UNITS {
(nA) = (nanoamp)
(mV) = (millivolt)
(uS) = (microsiemens)
}
PARAMETER {
tau1 = 15 (ms) <1e9,1e9>
tau2 = 150 (ms) <1e9,1e9>
: tau12 = 0.05 (ms) <1e9,1e9>
tau12 = 0.2 (ms) <1e9,1e9>
: tau22 = 5.3 (ms) <1e9,1e9>
tau22 = 1.0 (ms) <1e9,1e9>
e = 0 (mV)
mg = 1
Smax = 125
c = 1
: c = 1.53775
r = 1
}
ASSIGNED {
v (mV)
i (nA)
i2 (nA)
S (1)
S2 (1)
gmax (uS)
mgblock (1)
factor (1)
factor2 (1)
total (1)
}
STATE {
A (1)
B (1)
A2 (1)
B2 (1)
}
INITIAL {
LOCAL tp
if (tau1/tau2 > .9999) {
tau1 = .9999*tau2
}
A = 0
B = 0
tp = (tau1*tau2)/(tau2  tau1) * log(tau2/tau1)
factor = exp(tp/tau1) + exp(tp/tau2)
factor = 1/factor
total = 0
if (tau12/tau22 > .9999) {
tau12 = .9999*tau22
}
A2 = 0
B2 = 0
tp = (tau12*tau22)/(tau22  tau12) * log(tau22/tau12)
factor2 = exp(tp/tau12) + exp(tp/tau22)
factor2 = 1/factor2
total = 0
}
BREAKPOINT {
SOLVE state METHOD cnexp
S = B  A
S2 = B2  A2
:if (S>=Smax) {S = Smax}
mgblock = 1.0 / (1.0 + 0.28 * exp(0.062(/mV) * v) )
i = gmax * r * S * (v  e) * mgblock
i2 = gmax * S2 * (v  e)
}
DERIVATIVE state {
A' = A/tau1
B' = B/tau2
A2' = A2/tau12
B2' = B2/tau22
}
NET_RECEIVE(w(uS)) {
: the factor c comes from the fact that the synaptic mechanism described in the paper
: is using the presynaptic membrane potential continuously to define the differential equation
: and in NEURON these synapses are implemented by event based synapses
if (S<Smax) {
state_discontinuity(A, A + factor*c)
state_discontinuity(B, B + factor*c)
}
state_discontinuity(A2, A2 + factor2)
state_discontinuity(B2, B2 + factor2)
gmax = w
total = total + 1
}
