Discharge hysteresis in motoneurons (Powers & Heckman 2015)

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Accession:183949
"Motoneuron activity is strongly influenced by the activation of persistent inward currents (PICs) mediated by voltage-gated sodium and calcium channels. ... It has recently been suggested that a number of factors other than PIC can contribute to delta F (firing rate differences between motoneurons) values, including mechanisms underlying spike frequency adaptation and spike threshold accommodation. In the present study, we used a set of compartmental models representing a sample of 20 motoneurons with a range of thresholds to investigate how several different intrinsic motoneuron properties can potentially contribute to variations in F values. ... Our results indicate that, although other factors can contribute, variations in discharge hysteresis and delta F values primarily reflect the contribution of dendritic PICs to motoneuron activation.
Reference:
1 . Powers RK, Heckman CJ (2015) Contribution of intrinsic motoneuron properties to discharge hysteresis and its estimation based on paired motor unit recordings: a simulation study. J Neurophysiol 114:184-98 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell;
Brain Region(s)/Organism:
Cell Type(s): Spinal cord lumbar motor neuron alpha cell;
Channel(s): I Na,p; I Na,t; I L high threshold; I K; I M; I K,Ca; I_AHP; I Calcium; I Sodium;
Gap Junctions:
Receptor(s):
Gene(s): Kv1.2 KCNA2; Kv1.9 Kv7.1 KCNQ1;
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Spike Frequency Adaptation;
Implementer(s): Powers, Randy [rkpowers at u.washington.edu];
Search NeuronDB for information about:  Spinal cord lumbar motor neuron alpha cell; I Na,p; I Na,t; I L high threshold; I K; I M; I K,Ca; I Sodium; I Calcium; I_AHP;
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Discharge_hysteresis
Model hoc files and output
README.txt
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pars2manyhocs.py *
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SetConductances2.hoc *
SlowM.csv
standard.csv
twobirampsdel.hoc *
                            
TITLE gh channel channel
: Hodgkin - Huxley h channel


NEURON {
	SUFFIX gh
	USEION k READ ek WRITE ik
	USEION na READ ena WRITE ina
	RANGE ghbar, ik, ina,htau, half, slp,inf
}

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

PARAMETER {
	v (mV)
	ghbar =.001 (mho/cm2) <0,1e9>
	htau = 50 (ms)
	half=-80 (mV)
	slp=8 (mV)
	ek = -77 (mV)
	ena = 50 (mV)
}
STATE {
	n
}
ASSIGNED {
	ik (mA/cm2)
	ina (mA/cm2)
	inf
}

INITIAL {
	rate(v)
	n = inf
}

BREAKPOINT {
	SOLVE states METHOD derivimplicit
	ik = 0.7*ghbar*n*(v - ek)
	ina = 0.3*ghbar*n*(v - ena)
}

DERIVATIVE states {	
	rate(v)
	n' = (inf - n)/htau
}
UNITSOFF

PROCEDURE rate(v(mV)) {	
	TABLE inf DEPEND half,slp FROM -100 TO 100 WITH 200
		inf = 1/(1+exp((v-half)/slp))
}
UNITSON

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