TITLE Persistent sodium current : Implemented in Rubin and Cleland (2006) J Neurophysiology : Adapted from Fransen et al (2004) Hippocampus INDEPENDENT { t FROM 0 TO 1 WITH 1 (ms) } UNITS { (mV) = (millivolt) (mA) = (milliamp) } NEURON { SUFFIX NaP USEION na READ ena WRITE ina RANGE gbar, ina, i } PARAMETER { gbar = 0.0 (mho/cm2) v ena (mV) } ASSIGNED { ina (mA/cm2) i (mA/cm2) minf (1) mtau (ms) hinf htau (ms) } STATE { m h } BREAKPOINT { SOLVE states METHOD cnexp ina = gbar * m * h * ( v - ena ) i = ina } INITIAL { settables(v) m = minf h = hinf } DERIVATIVE states { settables(v) m' = ( minf - m ) / mtau h' = ( hinf - h ) / htau } UNITSOFF PROCEDURE settables(v) { TABLE minf, mtau, hinf, htau FROM -120 TO 40 WITH 641 if (v < -65 ) { minf = 0 } else{ minf = 1 / ( 1 + exp( -(v + 48.7) / 4.4 ) ) } if( v == -38.0 ) { mtau = .0013071895424837 :limit as v --> -38, a discontinuity in the mtau function }else{ mtau = 1 / ((.091 * 1000 * (v + 38))/(1 - exp(-(v + 38)/5)) + (-.062 * 1000 * (v + 38))/(1 - exp((v + 38)/5))) } :::::::::: change started here if (v > -45 ) { hinf = 0 } else{ hinf = 1 / ( 1 + exp((v + 48.8) / 9.98 )) } ::::::::::: and ended here :hinf = 1 / ( 1 + exp((v + 48.8) / 9.98 )) htau = 1 / ((-2.88*.001*(v + 17.049))/(1 - exp((v - 49.1)/4.63)) + (6.94*.001*(v + 64.409))/(1 - exp(-(v + 447)/2.63))) } UNITSON