A simplified cerebellar Purkinje neuron (the PPR model) (Brown et al. 2011)

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Accession:126637
These models were implemented in NEURON by Sherry-Ann Brown in the laboratory of Leslie M. Loew. The files reproduce Figures 2c-f from Brown et al, 2011 "Virtual NEURON: a Strategy For Merged Biochemical and Electrophysiological Modeling".
Reference:
1 . Brown SA, Moraru II, Schaff JC, Loew LM (2011) Virtual NEURON: a strategy for merged biochemical and electrophysiological modeling. J Comput Neurosci 31:385-400 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Dendrite;
Brain Region(s)/Organism: Cerebellum;
Cell Type(s): Cerebellum Purkinje GABA cell;
Channel(s): I Na,p; I p,q; I A; I K; I M; I K,Ca; I Sodium; I Calcium; I Potassium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Dendritic Action Potentials; Simplified Models; Active Dendrites; Influence of Dendritic Geometry; Detailed Neuronal Models; Intrinsic plasticity; Methods; Synaptic Integration;
Implementer(s): Brown, Sherry-Ann [sabrown at student.uchc.edu];
Search NeuronDB for information about:  Cerebellum Purkinje GABA cell; I Na,p; I p,q; I A; I K; I M; I K,Ca; I Sodium; I Calcium; I Potassium;
TITLE gsquid.mod   squid potassium channel
 
COMMENT
This is the original Hodgkin-Huxley treatment for the set of sodium, potassium, and leakage channels found in the squid giant axon membrane.("A quantitative description of membrane current and its application 
conduction and excitation in nerve" J.Physiol. (Lond.) 117:500-544 (1952).)
Membrane voltage is in absolute mV and has been reversed in polarity
from the original HH convention and shifted to reflect a resting potential
of close to -65 mV. (This text was written by SW Jaslove  6 March, 1992.)
ENDCOMMENT
 
UNITS {
        (mA) = (milliamp)
        (mV) = (millivolt)
}
 
NEURON {
        SUFFIX Khh
        USEION k WRITE ik
        RANGE   gk,  gkbar, ik
        GLOBAL  ninf, nexp
}
 
INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}
 
PARAMETER {
        v (mV)
        celsius = 37 (degC)
        dt (ms)
        gkbar = .036 (mho/cm2)
        ek = -85(mV)
	non = 1
}
 
STATE {
         n
}
 
ASSIGNED {
        ik (mA/cm2)
        gk ninf nexp
}
 
BREAKPOINT {
        SOLVE states
        gk  = gkbar*n*n*n*n

        ik = gk*(v - ek)      
}
 
UNITSOFF
 
INITIAL {
	rates(v)
	n = ninf
}

PROCEDURE states() {  :Computes state variable n 
        rates(v)      :             at the current v and dt.
        n = non * (n + nexp*(ninf-n))
}
 
PROCEDURE rates(v) {  :Computes rate and other constants at current v.
                      :Call once from HOC to initialize inf at resting v.
        LOCAL  q10, tinc, alpha, beta, sum
        TABLE ninf, nexp DEPEND dt, celsius FROM -400 TO 300 WITH 700
        q10 = 3^((celsius - 37)/10)
        tinc = -dt * q10
                :"n" potassium activation system
        alpha = .01*vtrap(-(v+55),10) 
        beta = .125*exp(-(v+65)/80)
        sum = alpha + beta
        ninf = alpha/sum
        nexp = 1 - exp(tinc*sum)
}

FUNCTION vtrap(x,y) {  :Traps for 0 in denominator of rate eqns.
        if (fabs(x/y) < 1e-6) {
                vtrap = y*(1 - x/y/2)
        }else{
                vtrap = x/(exp(x/y) - 1)
        }
}
 
UNITSON