TITLE I-h channel from Magee 1998 for distal dendrites UNITS { (mA) = (milliamp) (mV) = (millivolt) } PARAMETER { v (mV) ehd (mV) celsius (degC) ghdbar=.0001 (mho/cm2) vhalfl=-90 (mV) vhalft=-75 (mV) a0t=0.011 (/ms) zetal=4 (1) zetat=2.2 (1) gmt=.4 (1) q10=4.5 qtl=1 } NEURON { SUFFIX hd2 NONSPECIFIC_CURRENT i RANGE ghdbar, vhalfl GLOBAL linf,taul } STATE { l } ASSIGNED { i (mA/cm2) linf taul ghd } INITIAL { rate(v) l=linf } BREAKPOINT { SOLVE states METHOD cnexp ghd = ghdbar*l i = ghd*(v-ehd) } FUNCTION alpl(v(mV)) { alpl = exp(1.e-3*zetal*(v-vhalfl)*9.648e4/(8.315*(273.16+celsius))) } FUNCTION alpt(v(mV)) { alpt = exp(1.e-3*zetat*(v-vhalft)*9.648e4/(8.315*(273.16+celsius))) } FUNCTION bett(v(mV)) { bett = exp(1.e-3*zetat*gmt*(v-vhalft)*9.648e4/(8.315*(273.16+celsius))) } DERIVATIVE states { : exact when v held constant; integrates over dt step rate(v) l' = (linf - l)/taul } PROCEDURE rate(v (mV)) { :callable from hoc LOCAL a,qt qt=q10^((celsius-33)/10) a = alpt(v) linf = 1/(1+ alpl(v)) taul = bett(v)/(qtl*qt*a0t*(1+a)) }