| 1 | TITLE Cerebellum Granule Cell Model |
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| 2 | |
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| 3 | COMMENT |
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| 4 | KDr channel |
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| 5 | Gutfreund parametrization |
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| 6 | |
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| 7 | Author: A. Fontana |
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| 8 | Last revised: 12.12.98 |
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| 9 | ENDCOMMENT |
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| 10 | |
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| 11 | NEURON { |
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| 12 | SUFFIX CGC_KV |
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| 13 | USEION k READ ek WRITE ik |
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| 14 | RANGE gkbar, ik, g, alpha_n, beta_n |
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| 15 | RANGE Aalpha_n, Kalpha_n, V0alpha_n |
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| 16 | RANGE Abeta_n, Kbeta_n, V0beta_n |
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| 17 | RANGE n_inf, tau_n |
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| 18 | RANGE comp2134_vcbdur, comp2134_vcinc, comp2134_vchold, comp2134_vchdur, comp2134_vcbase, comp2134_vcsteps |
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| 19 | |
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| 20 | } |
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| 21 | |
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| 22 | UNITS { |
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| 23 | (mA) = (milliamp) |
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| 24 | (mV) = (millivolt) |
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| 25 | } |
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| 26 | |
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| 27 | PARAMETER { |
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| 28 | :Kbeta_n = -0.0125 (/mV) |
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| 29 | |
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| 30 | Aalpha_n = -0.01 (/ms-mV) |
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| 31 | Kalpha_n = -10 (mV) |
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| 32 | V0alpha_n = -25 (mV) |
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| 33 | Abeta_n = 0.125 (/ms) |
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| 34 | |
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| 35 | Kbeta_n = -80 (mV) |
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| 36 | V0beta_n = -35 (mV) |
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| 37 | v (mV) |
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| 38 | gkbar= 0.003 (mho/cm2) : 0.0015 |
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| 39 | ek = -84.69 (mV) |
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| 40 | celsius = 30 (degC) |
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| 41 | |
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| 42 | comp2134_vcbdur = 100.0 |
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| 43 | comp2134_vcinc = 10.0 |
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| 44 | comp2134_vchold = -71.0 |
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| 45 | comp2134_vchdur = 30.0 |
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| 46 | comp2134_vcbase = -69.0 |
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| 47 | comp2134_vcsteps = 8.0 |
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| 48 | |
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| 49 | } |
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| 50 | |
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| 51 | STATE { |
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| 52 | n |
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| 53 | } |
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| 54 | |
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| 55 | ASSIGNED { |
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| 56 | ik (mA/cm2) |
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| 57 | n_inf |
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| 58 | tau_n (ms) |
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| 59 | g (mho/cm2) |
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| 60 | alpha_n (/ms) |
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| 61 | beta_n (/ms) |
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| 62 | } |
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| 63 | |
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| 64 | INITIAL { |
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| 65 | rate(v) |
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| 66 | n = n_inf |
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| 67 | } |
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| 68 | |
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| 69 | BREAKPOINT { |
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| 70 | SOLVE states METHOD derivimplicit |
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| 71 | g = gkbar*n*n*n*n |
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| 72 | ik = g*(v - ek) |
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| 73 | alpha_n = alp_n(v) |
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| 74 | beta_n = bet_n(v) |
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| 75 | } |
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| 76 | |
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| 77 | DERIVATIVE states { |
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| 78 | rate(v) |
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| 79 | n' =(n_inf - n)/tau_n |
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| 80 | } |
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| 81 | |
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| 82 | FUNCTION alp_n(v(mV))(/ms) { LOCAL Q10 |
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| 83 | Q10 = 3^((celsius-6.3(degC))/10(degC)) |
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| 84 | alp_n = Q10*Aalpha_n*linoid(v-V0alpha_n, Kalpha_n) |
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| 85 | } |
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| 86 | |
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| 87 | FUNCTION bet_n(v(mV))(/ms) { LOCAL Q10 |
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| 88 | Q10 = 3^((celsius-6.3(degC))/10(degC)) |
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| 89 | bet_n = Q10*Abeta_n*exp((v-V0beta_n)/Kbeta_n) |
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| 90 | } |
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| 91 | |
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| 92 | PROCEDURE rate(v (mV)) {LOCAL a_n, b_n |
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| 93 | a_n = alp_n(v) |
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| 94 | b_n = bet_n(v) |
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| 95 | tau_n = 1/(a_n + b_n) |
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| 96 | n_inf = a_n/(a_n + b_n) |
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| 97 | } |
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| 98 | |
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| 99 | FUNCTION linoid(x (mV),y (mV)) (mV) { |
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| 100 | if (fabs(x/y) < 1e-6) { |
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| 101 | linoid = y*(1 - x/y/2) |
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| 102 | }else{ |
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| 103 | linoid = x/(exp(x/y) - 1) |
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| 104 | } |
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| 105 | } |
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