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: Reference: Colbert and Pan 2002
NEURON {
SUFFIX NaTa
USEION na READ ena WRITE ina
RANGE gbar, g, ina
}
UNITS {
(S) = (siemens)
(mV) = (millivolt)
(mA) = (milliamp)
}
PARAMETER {
gbar = 0.00001 (S/cm2)
malphaF = 0.182
mbetaF = 0.124
mvhalf = -48 (mV)
mk = 6 (mV)
halphaF = 0.015
hbetaF = 0.015
hvhalf = -69 (mV)
hk = 6 (mV)
}
ASSIGNED {
v (mV)
ena (mV)
ina (mA/cm2)
g (S/cm2)
celsius (degC)
mInf
mTau
mAlpha
mBeta
hInf
hTau
hAlpha
hBeta
}
STATE {
m
h
}
BREAKPOINT {
SOLVE states METHOD cnexp
g = gbar*m*m*m*h
ina = g*(v-ena)
}
DERIVATIVE states {
rates()
m' = (mInf-m)/mTau
h' = (hInf-h)/hTau
}
INITIAL{
rates()
m = mInf
h = hInf
}
PROCEDURE rates(){
LOCAL qt
qt = 2.3^((celsius-23)/10)
UNITSOFF
mAlpha = malphaF * vtrap(-(v - mvhalf), mk)
mBeta = mbetaF * vtrap((v - mvhalf), mk)
mInf = mAlpha/(mAlpha + mBeta)
mTau = (1/(mAlpha + mBeta))/qt
hAlpha = halphaF * vtrap(v - hvhalf, hk) : ng - adjusted this to match actual Colbert & Pan values for soma model
hBeta = hbetaF * vtrap(-(v - hvhalf), hk) : ng - adjusted this to match actual Colbert & Pan values for soma model
hInf = hAlpha/(hAlpha + hBeta)
hTau = (1/(hAlpha + hBeta))/qt
UNITSON
}
FUNCTION vtrap(x, y) { : Traps for 0 in denominator of rate equations
UNITSOFF
if (fabs(x / y) < 1e-6) {
vtrap = y * (1 - x / y / 2)
} else {
vtrap = x / (exp(x / y) - 1)
}
UNITSON
}
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