: Fast Ca2+ & V-dependent K+ channel : from Durstewitz & Gabriel (2006), Cerebral Cortex NEURON { SUFFIX Kc USEION k READ ki, ko WRITE ik USEION ca READ cai RANGE gk, gKcbar } UNITS { (mM) = (milli/liter) (mA) = (milliamp) (mV) = (millivolt) } PARAMETER { cai (mM) gKcbar= 0.0022 (mho/cm2) } ASSIGNED { v (mV) ik (mA/cm2) cinf ctau (ms) gk (mho/cm2) ek (mV) ki (mM) ko (mM) } STATE { c } INITIAL { rate(v) c = cinf } BREAKPOINT { SOLVE states METHOD derivimplicit gk = gKcbar*c*c ek = 25*log(ko/ki) ik = gk*(v-ek) } DERIVATIVE states { rate(v) c' = (cinf-c)/ctau } UNITSOFF FUNCTION calf(v (mV), cai (mM)) (/ms) { LOCAL vs, va vs=v+40*log10(1000*cai) va=vs+18 if (fabs(va)<1e-04){ calf = -0.0064*(-12-va*0.5) } else { calf = (-0.0064*vs-0.1152)/(-1+exp(-va/12)) } } FUNCTION cbet(v (mV), cai (mM))(/ms) { LOCAL vs vs=v+40*log10(cai*1000)+152 cbet = 1.7*exp(-vs/30) } PROCEDURE rate(v) { LOCAL csum, ca, cb ca=calf(v,cai) cb=cbet(v, cai) csum = ca+cb cinf = ca/csum ctau = 1/csum if (ctau<1.1) { ctau = 1.1 } } UNITSON