A detailed Purkinje cell model (Masoli et al 2015)

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Accession:229585
The Purkinje cell is one of the most complex type of neuron in the central nervous system and is well known for its massive dendritic tree. The initiation of the action potential was theorized to be due to the high calcium channels presence in the dendritic tree but, in the last years, this idea was revised. In fact, the Axon Initial Segment, the first section of the axon was seen to be critical for the spontaneous generation of action potentials. The model reproduces the behaviours linked to the presence of this fundamental sections and the interplay with the other parts of the neuron.
Reference:
1 . Masoli S, Solinas S, D'Angelo E (2015) Action potential processing in a detailed Purkinje cell model reveals a critical role for axonal compartmentalization. Front Cell Neurosci 9:47 [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: Cerebellum;
Cell Type(s): Cerebellum Purkinje GABA cell;
Channel(s): I Sodium; I Calcium; I Na,t; I K;
Gap Junctions:
Receptor(s):
Gene(s): Cav2.1 CACNA1A; Cav3.1 CACNA1G; Cav3.2 CACNA1H; Cav3.3 CACNA1I; Nav1.6 SCN8A; Kv1.1 KCNA1; Kv1.5 KCNA5; Kv3.3 KCNC3; Kv3.4 KCNC4; Kv4.3 KCND3; KCa1.1 KCNMA1; KCa2.2 KCNN2; KCa3.1 KCNN4; Kir2.1 KCNJ2; HCN1;
Transmitter(s):
Simulation Environment: NEURON; Python;
Model Concept(s): Bursting; Detailed Neuronal Models; Action Potentials; Action Potential Initiation; Axonal Action Potentials;
Implementer(s): Masoli, Stefano [stefano.masoli at unipv.it]; Solinas, Sergio [solinas at unipv.it];
Search NeuronDB for information about:  Cerebellum Purkinje GABA cell; I Na,t; I K; I Sodium; I Calcium;
TITLE Low threshold calcium current Cerebellum Purkinje Cell Model

COMMENT

Kinetics adapted to fit the Cav3.1 Iftinca et al 2006, Temperature dependence of T-type Calcium channel gating, NEUROSCIENCE

Reference: Anwar H, Hong S, De Schutter E (2010) Controlling Ca2+-activated K+ channels with models of Ca2+ buffering in Purkinje cell. Cerebellum*

*Article available as Open Access

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/20981513

Written by Haroon Anwar, Computational Neuroscience Unit, Okinawa Institute of Science and Technology, 2010.
Contact: Haroon Anwar (anwar@oist.jp)

Suffix from CaT3_1 to CaV3_1

ENDCOMMENT


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

NEURON {
        SUFFIX Cav3_1
        USEION ca READ cai, cao WRITE ica VALENCE 2
        RANGE g, pcabar, minf, taum, hinf, tauh
	RANGE ica, m ,h

    }

UNITS {
        (molar) = (1/liter)
        (mV) =  (millivolt)
        (mA) =  (milliamp)
        (mM) =  (millimolar)

}

CONSTANT {
	F = 9.6485e4 (coulombs)
	R = 8.3145 (joule/kelvin)
	q10 = 3
}

PARAMETER {
        v               (mV)
        celsius (degC)
        eca (mV)
	pcabar  = 2.5e-4 (cm/s)
        cai  (mM)           : adjusted for eca=120 mV
	cao  (mM)
	
	v0_m_inf = -52 (mV)
	v0_h_inf = -72 (mV)
	k_m_inf = -5 (mV)
	k_h_inf = 7  (mV)
	
	C_tau_m = 1
	A_tau_m = 1.0
	v0_tau_m1 = -40 (mV)
	v0_tau_m2 = -102 (mV)
	k_tau_m1 = 9 (mV)
	k_tau_m2 = -18 (mV)
	
	C_tau_h = 15
	A_tau_h = 1.0
	v0_tau_h1 = -32 (mV)
	k_tau_h1 = 7 (mV)
	
    }
    

STATE {
        m h
}

ASSIGNED {
        ica     (mA/cm2)
	g        (coulombs/cm3) 
        minf
        taum   (ms)
        hinf
        tauh   (ms)
	T (kelvin)
	E (volt)
	zeta
	qt
}

BREAKPOINT {
	SOLVE castate METHOD cnexp 

        ica = (1e3) *pcabar*m*m *h * g
}

DERIVATIVE castate {
        evaluate_fct(v)

        m' = (minf - m) / taum
        h' = (hinf - h) / tauh
}

FUNCTION ghk( v (mV), ci (mM), co (mM), z )  (coulombs/cm3) {
    E = (1e-3) * v
      zeta = (z*F*E)/(R*T)


    if ( fabs(1-exp(-zeta)) < 1e-6 ) {
        ghk = (1e-6) * (z*F) * (ci - co*exp(-zeta)) * (1 + zeta/2)
    } else {
        ghk = (1e-6) * (z*zeta*F) * (ci - co*exp(-zeta)) / (1-exp(-zeta))
    }
}


UNITSOFF
INITIAL {
	
	T = kelvinfkt (celsius)

        evaluate_fct(v)
        m = minf
        h = hinf
	qt = q10^((celsius-37 (degC))/10 (degC))
}

PROCEDURE evaluate_fct(v(mV)) { 

        minf = 1.0 / ( 1 + exp((v  - v0_m_inf)/k_m_inf) )
        hinf = 1.0 / ( 1 + exp((v - v0_h_inf)/k_h_inf) )
        if (v<=-90) {
	taum = 1
	} else {
	taum = ( C_tau_m + A_tau_m / (exp((v - v0_tau_m1)/ k_tau_m1) + exp((v - v0_tau_m2)/k_tau_m2))) / qt
	}
	tauh = ( C_tau_h + A_tau_h / exp((v - v0_tau_h1)/k_tau_h1) ) / qt
	g = ghk(v, cai, cao, 2)
}

FUNCTION kelvinfkt( t (degC) )  (kelvin) {
    kelvinfkt = 273.19 + t
}

UNITSON

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