COMMENT Maciej T. Lazarewicz, mlazarew@seas.upenn.edu ENDCOMMENT NEURON { SUFFIX kdr USEION k WRITE ik RANGE gkbar, ik } UNITS { (mA) = (milliamp) (mV) = (millivolt) (mS) = (millisiemens) } PARAMETER { gkbar = 15 (mS/cm2) ek = -75 (mV) } ASSIGNED { v (mV) ik (mA/cm2) ninf (1) taun (ms) } STATE { n } INITIAL { rates(v) n = ninf } BREAKPOINT { SOLVE states METHOD cnexp ik = (1e-3) * gkbar * n * (v-ek) } DERIVATIVE states { rates(v) n' = (ninf-n)/taun } PROCEDURE rates(v(mV)) { LOCAL a, b a = fun3(v, -24.9, -0.016, -5) b = fun1(v, -40, 0.25, -40) ninf = a/(a+b) taun = 1.0/(a+b) } COMMENT Maciej T. Lazarewicz, mlazarew@seas.upenn.edu ENDCOMMENT :------------------------------------------------------------------- FUNCTION fun1(v(mV),V0(mV),A(/ms),B(mV))(/ms) { fun1 = A*exp((v-V0)/B) } FUNCTION fun2(v(mV),V0(mV),A(/ms),B(mV))(/ms) { fun2 = A/(exp((v-V0)/B)+1) } FUNCTION fun3(v(mV),V0(mV),A(/ms),B(mV))(/ms) { if(fabs((v-V0)/B)<1e-6) { :if(v==V0) { fun3 = A*B/1(mV) * (1- 0.5 * (v-V0)/B) } else { fun3 = A/1(mV)*(v-V0)/(exp((v-V0)/B)-1) } } FUNCTION min(x,y) { if (x<=y){ min = x }else{ min = y } }