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(2):385-400 [PubMed]
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 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 cell; I Na,p; I p,q; I A; I K; I M; I K,Ca; I Sodium; I Calcium; I Potassium;
TITLE BK calcium-activated potassium current
: Calcium activated K channel.

COMMENT
  from "An Active Membrane Model of the Cerebellar Purkinje Cell
        1. Simulation of Current Clamp in Slice"
ENDCOMMENT

UNITS {
	(molar) = (1/liter)
}

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


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

NEURON {
	SUFFIX KC3
	USEION ca READ cai
	USEION k WRITE ik
	RANGE gkbar,gk,zinf,ik
}


PARAMETER {
	celsius=37	(degC)
	v		(mV)
	gkbar=.08	(mho/cm2)	: Maximum Permeability
	cai = .04e-3	(mM)
	ek  = -85	(mV)
	dt		(ms)
	mon = 1
	zon = 1
}


ASSIGNED {
	ik		(mA/cm2)
	minf
	mexp
	zinf
	zexp
	gk
}

STATE {	m z }		: fraction of open channels

BREAKPOINT {
	SOLVE state
:	gk = gkbar*m*z*z
	ik = gkbar*m*z*z*(v - ek)
}
:UNITSOFF
:LOCAL fac

:if state_cagk is called from hoc, garbage or segmentation violation will
:result because range variables won't have correct pointer.  This is because
: only BREAKPOINT sets up the correct pointers to range variables.
PROCEDURE state() {	: exact when v held constant; integrates over dt step
	rate(v, cai)
	m = mon * (m + mexp*(minf - m))
	z = zon * (z + zexp*(zinf - z))
	VERBATIM
	return 0;
	ENDVERBATIM
}

INITIAL {
	rate(v, cai)
	m = minf
	z = zinf
}

FUNCTION alp(v (mV), ca (mM)) (1/ms) { :callable from hoc
	alp = 400/(ca*1000)
}

FUNCTION bet(v (mV)) (1/ms) { :callable from hoc
	bet = 0.11/exp((v-35)/14.9)
}

PROCEDURE rate(v (mV), ca (mM)) { :callable from hoc
	LOCAL a,b
	a = alp(v,ca)
	zinf = 1/(1+a)
	zexp = (1 - exp(-dt/10))
	b = bet(v)
	minf = 7.5/(7.5+b)
	mexp = (1 - exp(-dt*(7.5+b)))
}
:UNITSON

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