COMMENT //****************************// // Created by Alon Polsky // // apmega@yahoo.com // // 2010 // //****************************// ENDCOMMENT TITLE NMDA synapse with depression NEURON { POINT_PROCESS glutamate NONSPECIFIC_CURRENT inmda,iampa RANGE del,Tspike,Nspike RANGE e ,gampamax,gnmdamax,local_v,inmda,iampa RANGE decayampa,decaynmda,dampa,dnmda RANGE gnmda,gampa GLOBAL n, gama,tau_ampa,taudampa,taudnmda GLOBAL tau1,tau2 :USEION canmda WRITE icanmda VALENCE 2 USEION ca WRITE ica GLOBAL icaconst } UNITS { (nA) = (nanoamp) (mV) = (millivolt) (nS) = (nanomho) (mM) = (milli/liter) F = 96480 (coul) R = 8.314 (volt-coul/degC) PI = (pi) (1) (mA) = (milliamp) (um) = (micron) } PARAMETER { icaconst =0.1 gnmdamax=1 (nS) gampamax=1 (nS) e= 0.0 (mV) tau1=50 (ms) tau2=2 (ms) tau_ampa=1 (ms) n=0.25 (/mM) gama=0.08 (/mV) dt (ms) v (mV) del=30 (ms) Tspike=10 (ms) Nspike=1 decayampa=.5 decaynmda=.5 taudampa=200 (ms):tau decay taudnmda=200 (ms):tau decay } ASSIGNED { inmda (nA) iampa (nA) gnmda (nS) local_v (mV):local voltage :icanmda (nA) ica (nA) } STATE { A (nS) B (nS) gampa (nS) dampa dnmda } INITIAL { gnmda=0 gampa=0 A=0 B=0 dampa=1 dnmda=1 :icanmda=0 } BREAKPOINT { LOCAL count SOLVE state METHOD cnexp FROM count=0 TO Nspike-1 { IF(at_time(count*Tspike+del)){ state_discontinuity( A, A+ gnmdamax*(dnmda)) state_discontinuity( B, B+ gnmdamax*(dnmda)) state_discontinuity( gampa, gampa+ gampamax*dampa) state_discontinuity( dampa, dampa* decayampa) state_discontinuity( dnmda, dnmda* decaynmda) } } gnmda=(A-B)/(1+n*exp(-gama*v) ) inmda =(1e-3)* gnmda * (v-e) iampa= (1e-3)*gampa* (v- e) local_v=v :icanmda=inmda/10 ica=inmda*0.1/(PI*diam)*icaconst inmda=inmda*.9 } DERIVATIVE state { A'=-A/tau1 B'=-B/tau2 gampa'=-gampa/tau_ampa dampa'=(1-dampa)/taudampa dnmda'=(1-dnmda)/taudnmda }