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129 lines
2.9 KiB
129 lines
2.9 KiB
2 years ago
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TITLE kif.mod DCN pyramidal cell model fast transient current
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COMMENT
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This model implements a fast transient potassium current from
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Dorsal Cochlear Nucleus Pyramidal cells
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based on kinetic data from Kanold and Manis (1999) and Kanold's dissertation (1999)
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-- 15 Jan 1999 P. Manis
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2/10/02. P. Manis.
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Pulled from pyr.mod 7/24/2014
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ENDCOMMENT
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UNITS {
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(mA) = (milliamp)
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(mV) = (millivolt)
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}
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NEURON {
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SUFFIX kif
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USEION k READ ek WRITE ik
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RANGE gkif, kif_a_inf, kif_i_inf : fast inactivating potassium current
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RANGE akif, gbar
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RANGE kif_a_tau, kif_i_tau
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RANGE kif_a_start, kif_i_start
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RANGE kif_ivh, kif_avh, kif_hivh
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}
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INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}
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PARAMETER {
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v (mV)
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celsius (degC)
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dt (ms)
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ek (mV) : = -81.5 (mV)
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ena (mV) : = 50.0 (mV)
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gbar = 0.0125 (mho/cm2) <0,1e9>
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kif_ivh = -89.6 (mV)
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kif_avh = -57.0 (mV)
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kif_hivh = -87.0 (mV)
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kif_a_start = -1 (1)
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kif_i_start = -1 (1)
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}
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STATE {
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kifa kifi
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}
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ASSIGNED {
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gkif (mho/cm2)
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ik (mA/cm2)
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kif_a_inf (1)
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kif_i_inf (1)
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kif_a_tau (ms)
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kif_i_tau (ms)
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akif ()
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q10 ()
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}
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BREAKPOINT {
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SOLVE states METHOD cnexp
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akif = kifa*kifa*kifa*kifa*kifi
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gkif = gbar*akif
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ik = gkif*(v - ek)
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}
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INITIAL {
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q10 = 3^((celsius - 22)/10 (degC))
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rates(v)
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if(kif_a_start < 0) { : if xx_(i/a)_start is > 0, then perturbation is done at onset of computations.
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kifa = kif_a_inf
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} else {
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kifa = kif_a_start
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}
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if(kif_i_start < 0) {
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kifi = kif_i_inf
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} else {
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kifi = kif_i_start
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}
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}
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DERIVATIVE states {
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rates(v)
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kifa' = (kif_a_inf - kifa) / kif_a_tau
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kifi' = (kif_i_inf - kifi) / kif_i_tau
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}
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PROCEDURE rates(v(mV)) { :Computes rate and other constants at current v.
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:Call once from HOC to initialize inf at resting v.
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: LOCAL alpha, beta, sum
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: TABLE kif_a_inf, kif_a_tau, kif_i_inf, kif_i_tau DEPEND celsius, kif_avh, kif_ivh FROM -200 TO 100 WITH 400
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: "kif" fast inactivation potassium channel - activation and inactivation
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kif_a_inf = kif_m(v)
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kif_i_inf = kif_h(v)
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kif_a_tau = kif_mt(v)
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kif_i_tau = kif_ht(v)
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}
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: Make these as functions so we can view them from hoc, although this
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: may slow things down a bit
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FUNCTION kif_m(v ) { : ikif activation
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kif_m = 1.0/(1+exp(-(v-kif_avh)/25.8 (mV)))
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}
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FUNCTION kif_h(v (mV)) { : ikif inactivation
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kif_h = 1.0/(1+exp((v-kif_ivh)/6.7 (mV)))
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}
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FUNCTION kif_mt(v (mV)) (ms) { : ikif activation tau
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LOCAL x
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x = 0.15 * exp((v-kif_avh)/10 (mV)) + 0.3 *exp(-(v-kif_avh)/10 (mV))
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x = 0.5 + (1.0 /x)
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kif_mt = (x * 1.0 (ms))/q10
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}
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FUNCTION kif_ht(v (mV)) (ms) { : ikif inactivation tau
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LOCAL x
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x = 0.015 * exp((v-kif_hivh)/20 (mV))+0.03*exp(-(v-kif_hivh)/20 (mV))
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x = 10 + (1./x)
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kif_ht = (x * 1.0 (ms)) /q10
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}
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