: Ih current
: Created 8/6/02 - nwg
: for the formulation of Angelo's data, the original parameter correspond to a maximum value of 250 ms. In their supplement data, this value is about 325 ms. So I corrected a value1.3
NEURON {
SUFFIX hpkj
NONSPECIFIC_CURRENT i
RANGE ghbar, eh, i
GLOBAL ninf, ntau
: THREADSAFE
}
UNITS {
(mA) = (milliamp)
(mV) = (millivolt)
(S) = (siemens)
}
CONSTANT {
q10 = 3
}
PARAMETER {
v (mV)
celsius (degC)
ghbar = .0001 (S/cm2)
eh = -30 (mV)
}
ASSIGNED {
i (mA/cm2)
qt
ninf
ntau
}
STATE {
n
}
INITIAL {
qt = q10^((celsius-22 (degC))/10 (degC))
rates(v)
n = ninf
}
BREAKPOINT {
SOLVE states METHOD cnexp
i = ghbar*n*(v - eh)
}
DERIVATIVE states {
rates(v)
n' = (ninf - n)/ntau
}
PROCEDURE rates(v (mV)) {
: ninf = 1/(1+exp((v+90.3+3)/9.9))
ninf = 1/(1+exp((v+90.3+3+3)/9.67))
ntau = 1000/(0.62*(exp((v+68)/-22)+exp((v+68)/7.14)))/qt/1.3
}