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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