COMMENT A synaptic current with two dual exponential function conductances, representing non-voltage-dependent AMPA and voltage-dependent NMDA components. The basic dual exponential conductance is given by: g = 0 for t < onset and g = gmax*((tau1*tau2)/(tau1-tau2)) * (exp(-(t-onset)/tau1)-exp(-(t-onset)/tau2)) for t > onset (tau1 and tau2 are fast and slow time constants) The synaptic current is: i = (gA + gN) * (v - e) i(nanoamps), g(micromhos); NMDA model taken from Mel, J. Neurophys. 70:1086-1101, 1993 BPG 1-12-00 ENDCOMMENT INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)} NEURON { POINT_PROCESS ANSynapse RANGE onset, gmax, e, i, g, gA, gN, tau1, tau2, Ntau1, Ntau2, eta, Mg, gamma, Nfrac NONSPECIFIC_CURRENT i } UNITS { (nA) = (nanoamp) (mV) = (millivolt) (umho) = (micromho) } PARAMETER { onset=0 (ms) tau1=.2 (ms) <1e-3,1e6> tau2=2 (ms) <1e-3,1e6> Nfrac=0.5 Ntau1=.66 (ms) <1e-3,1e6> Ntau2=80 (ms) <1e-3,1e6> eta=0.33 (/mM) Mg=1 (mM) gamma=0.06 (/mV) gmax=0 (umho) <0,1e9> e=0 (mV) v (mV) } ASSIGNED { i (nA) g (umho) gA (umho) gN (umho) Agmax (umho) Ngmax (umho)} INITIAL { Agmax = (1-Nfrac)*gmax Ngmax = Nfrac*gmax } BREAKPOINT { gA = Agmax*((tau1*tau2)/(tau1-tau2))*duale((t-onset)/tau1,(t-onset)/tau2) gN = Ngmax*((Ntau1*Ntau2)/(Ntau1-Ntau2))*duale((t-onset)/Ntau1,(t-onset)/Ntau2) gN = gN / (1 + (eta*Mg*exp(-gamma*v))) g = gA + gN i = g*(v - e) } FUNCTION duale(x,y) { if (x < 0 || y < 0) { duale = 0 }else{ duale = exp(-x) - exp(-y) } }