TITLE H-current NEURON { SUFFIX h RANGE gbar,vhalf, K, taun, ninf, g :range variables USEION na READ ena WRITE ina : which ions to use and how to treat them ena = reversal pot for Na : NONSPECIFIC_CURRENT i } UNITS { (um) = (micrometer) (mA) = (milliamp) (uA) = (microamp) (mV) = (millivolt) (pmho) = (picomho) (mmho) = (millimho) } INDEPENDENT {t FROM 0 TO 1 WITH 100 (ms)} PARAMETER { : parameters that can be entered when function is called in cell-setup dt (ms) v (mV) ena=0 (mV) K = 8.5 (mV) gbar = 0.1 (mmho/cm2) : this is the somatic value. dendritic value is 6x higher vhalf =-90 (mV) } STATE { : the unknown parameters to be solved in the DEs n } ASSIGNED { : parameters neede to solve DE ina (mA/cm2) ninf taun (ms) g } INITIAL { : initialize the following parameter using states() states() n = ninf g = gbar*n ina = g*(v-ena)*(0.001) } BREAKPOINT { SOLVE h METHOD derivimplicit g = gbar*n ina = g*(v-ena)*(0.001) } DERIVATIVE h { states() n' =(ninf - n)/taun } PROCEDURE states() { if (v > -30) { taun = 1 } else { : taun = -0.5(ms/mV)*v - 10(ms) taun = -0.5(ms/mV)*v - 10(ms) } ninf = 1 - (1 / (1 + exp((vhalf - v)/K))) }