TITLE Hyperpolarization-activated, CN-gated channel (voltage dependent) COMMENT Hyperpolarization-activated, CN-gated channel (voltage dependent) Ions: non-specific Style: quasi-ohmic From: Magee 1998 for distal dendrites, default values are for dendrites and low Na Updates: 2014 December (Marianne Bezaire): documented ENDCOMMENT UNITS { (mA) = (milliamp) (mV) = (millivolt) } PARAMETER { v (mV) e (mV) celsius (degC) gmax=.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 ch_HCNp NONSPECIFIC_CURRENT i RANGE gmax, vhalfl, myi, e, g GLOBAL linf,taul } STATE { l } ASSIGNED { i (mA/cm2) myi (mA/cm2) linf taul g } INITIAL { rate(v) l=linf } BREAKPOINT { SOLVE states METHOD cnexp g = gmax*l i = g*(v-e) myi = i } FUNCTION alpl(v(mV)) { alpl = exp(0.0378*zetal*(v-vhalfl)) } FUNCTION alpt(v(mV)) { alpt = exp(0.0378*zetat*(v-vhalft)) } FUNCTION bett(v(mV)) { bett = exp(0.0378*zetat*gmt*(v-vhalft)) } 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)) }