GPi/GPe neuron models (Johnson and McIntyre 2008)

 Download zip file   Auto-launch 
Help downloading and running models
Accession:114685
Model files for two types of non-human primate neurons used in the paper: simplified versions of 1) a GPi neuron and 2) a GPe axon collateralizing in GPi en route to STN.
Reference:
1 . Johnson MD, McIntyre CC (2008) Quantifying the neural elements activated and inhibited by globus pallidus deep brain stimulation. J Neurophysiol 100:2549-63 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Axon;
Brain Region(s)/Organism:
Cell Type(s): Globus pallidus neuron;
Channel(s): I Sodium; I Calcium; I Potassium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Simplified Models; Axonal Action Potentials; Parkinson's; Extracellular Fields;
Implementer(s): Johnson, Matthew D [johnsom11 at ccf.org];
Search NeuronDB for information about:  I Sodium; I Calcium; I Potassium;
TITLE Axon Node channels
: 
: Based on axon model from McIntyre2004
:
: Fast Na+, Persistant Na+, Slow K+, and Leakage currents 
:    responsible for nodal action potential
: Iterative equations H-H notation rest = -75 mV

INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}

NEURON {
    SUFFIX axnode75
    NONSPECIFIC_CURRENT ina
    NONSPECIFIC_CURRENT inap
    NONSPECIFIC_CURRENT ik
    NONSPECIFIC_CURRENT il
    RANGE gnapbar, gnabar, gkbar, gl, ena, ek, el
    RANGE mp_inf, m_inf, h_inf, s_inf
    RANGE tau_mp, tau_m, tau_h, tau_s
}

UNITS {
    (mA) = (milliamp)
    (mV) = (millivolt)
}

PARAMETER {
    gnapbar = 0.01      (mho/cm2)
    gnabar  = 3.0       (mho/cm2)
    gkbar   = 0.08      (mho/cm2)
    gl	    = 0.007     (mho/cm2)
    ena     = 55.0      (mV)
    ek      = -85.0     (mV)
    el	    = -85.0     (mV)
    celsius             (degC)
    dt                  (ms)
    v                   (mV)
    vshift=5
    vtraub=-80
    ampA = 0.01
    ampB = 27
    ampC = 10.2
    bmpA = 0.00025
    bmpB = 34
    bmpC = 10
    amA = 1.86
    amB = 21.4
    amC = 10.3
    bmA = 0.086
    bmB = 25.7
    bmC = 9.16
    ahA = 0.062
    ahB = 114.0
    ahC = 11.0
    bhA = 2.3
    bhB = 31.8
    bhC = 13.4
    asA = 0.3
    asB = -27
    asC = -5
    bsA = 0.03
    bsB = 10
    bsC = -1
}

STATE {
    mp m h s
}

ASSIGNED {
    inap    (mA/cm2)
    ina     (mA/cm2)
    ik      (mA/cm2)
    il      (mA/cm2)
    mp_inf
    m_inf
    h_inf
    s_inf
    tau_mp
    tau_m
    tau_h
    tau_s
    q10_1
    q10_2
    q10_3
}

BREAKPOINT {
    SOLVE states METHOD cnexp
    inap = gnapbar * mp*mp*mp * (v - ena)
    ina = gnabar * m*m*m*h * (v - ena)
    ik   = gkbar * s * (v - ek)
    il   = gl * (v - el)
}

DERIVATIVE states {   : exact Hodgkin-Huxley equations
    evaluate_fct(v)
    mp'= (mp_inf - mp) / tau_mp
    m' = (m_inf - m) / tau_m
    h' = (h_inf - h) / tau_h
    s' = (s_inf - s) / tau_s
}

UNITSOFF

INITIAL {

    : Q10 adjustment
    q10_1 = 2.2 ^ ((celsius-20)/ 10 )
    q10_2 = 2.9 ^ ((celsius-20)/ 10 )
    q10_3 = 3.0 ^ ((celsius-36)/ 10 )

    evaluate_fct(v)
    mp = mp_inf
    m = m_inf
    h = h_inf
    s = s_inf
}

PROCEDURE evaluate_fct(v(mV)) { LOCAL a,b,v2

    v2 = v - vshift

    a = q10_1*vtrap1(v2)
    b = q10_1*vtrap2(v2)
    tau_mp = 1 / (a + b)
    mp_inf = a / (a + b)

    a = q10_1*vtrap6(v2)
    b = q10_1*vtrap7(v2)
    tau_m = 1 / (a + b)
    m_inf = a / (a + b)

    a = q10_2*vtrap8(v2)
    b = q10_2*bhA / (1 + Exp(-(v2+bhB)/bhC))
    tau_h = 1 / (a + b)
    h_inf = a / (a + b)

    a = q10_3*asA / (Exp((v2-vtraub+asB)/asC) + 1) 
    b = q10_3*bsA / (Exp((v2-vtraub+bsB)/bsC) + 1)
    tau_s = 1 / (a + b)
    s_inf = a / (a + b)
}

FUNCTION vtrap(x) {
    if (x < -50) {
        vtrap = 0
    }else{
        vtrap = bsA / (Exp((x+bsB)/bsC) + 1)
    }
}

FUNCTION vtrap1(x) {
    if (fabs((x+ampB)/ampC) < 1e-6) {
        vtrap1 = ampA*ampC
    }else{
        vtrap1 = (ampA*(x+ampB)) / (1 - Exp(-(x+ampB)/ampC))
    }
}

FUNCTION vtrap2(x) {
    if (fabs((x+bmpB)/bmpC) < 1e-6) {
        vtrap2 = bmpA*bmpC : Ted Carnevale bug fix removed minus sign
    }else{
        vtrap2 = (bmpA*(-(x+bmpB))) / (1 - Exp((x+bmpB)/bmpC))
    }
}

FUNCTION vtrap6(x) {
    if (fabs((x+amB)/amC) < 1e-6) {
        vtrap6 = amA*amC
    }else{
        vtrap6 = (amA*(x+amB)) / (1 - Exp(-(x+amB)/amC))
    }
}

FUNCTION vtrap7(x) {
    if (fabs((x+bmB)/bmC) < 1e-6) {
        vtrap7 = bmA*bmC : Ted Carnevale bug fix removed minus sign
    }else{
        vtrap7 = (bmA*(-(x+bmB))) / (1 - Exp((x+bmB)/bmC))
    }
}

FUNCTION vtrap8(x) {
    if (fabs((x+ahB)/ahC) < 1e-6) {
        vtrap8 = ahA*ahC : Ted Carnevale bug fix removed minus sign
    }else{
        vtrap8 = (ahA*(-(x+ahB))) / (1 - Exp((x+ahB)/ahC)) 
    }
}

FUNCTION Exp(x) {
    if (x < -100) {
        Exp = 0
    }else{
        Exp = exp(x)
    }
}

UNITSON

Loading data, please wait...