Double cable myelinated axon (Layer 5 pyramidal neuron; Cohen et al 2020)

 Download zip file 
Help downloading and running models
Accession:260967
The periaxonal space in myelinated axons is conductive (~50 ohm cm). Together with a rapidly charging myelin sheath and relatively sealed paranodes, periaxonal conduction shapes the saltating voltage profiles of transaxonal (Vm), transmyelin (Vmy) and transfibre (Vmym) potentials. This model exemplifies double cable saltatory conduction across both time and space, and is the same cell (#6) as seen in Movie S4 of Cohen et al. 2020. This model version allows one to visualize and manipulate the controlling parameters of a propagating action potential. Further notes: The corresponding potentials in NEURON to those named above are v, vext (or vext[0]) and v+vext, respectively. The loaded biophysical parameters were those optimized for this cell (Cohen et al. 2020).
Reference:
1 . Cohen CCH, Popovic MA, Klooster J, Weil M, Möbius W, Nave K, Kole MHP (2020) Saltatory Conduction along Myelinated Axons Involves a Periaxonal Nanocircuit Cell
Model Information (Click on a link to find other models with that property)
Model Type: Axon; Channel/Receptor; Dendrite; Extracellular; Glia; Neuron or other electrically excitable cell;
Brain Region(s)/Organism:
Cell Type(s): Neocortex L5/6 pyramidal GLU cell; Myelinated neuron;
Channel(s): Ca pump; I Calcium; I h; I K,Ca; I K,leak; I L high threshold; I T low threshold; I M; I Na,p; I Na,t; I Sodium; I Potassium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potentials; Active Dendrites; Axonal Action Potentials; Conductance distributions; Conductances estimation; Detailed Neuronal Models; Electrotonus; Extracellular Fields; Membrane Properties; Multiple sclerosis; Parameter sensitivity; Double cable;
Implementer(s): Cohen, Charles CH [c.cohen at gmx.com]; Kole, Maarten [m.kole at nin.knaw.nl];
Search NeuronDB for information about:  Neocortex L5/6 pyramidal GLU cell; I Na,p; I Na,t; I L high threshold; I T low threshold; I K,leak; I M; I h; I K,Ca; I Sodium; I Calcium; I Potassium; Ca pump; 
COMMENT

Made threadsafe (CCohen)

ENDCOMMENT

TITLE Ih-current

UNITS {
	
	(mA) = (milliamp)
	(mV) = (millivolt)
    (mM) = (milli/liter)
}

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

PARAMETER {
	
	dt 				(ms)
	v 				(mV)
    eh = -47  		(mV) 		: ih-reversal potential by Berger	  
	gbar = 0.00015	(mho/cm2)	: density on dendrite assuming 150pA current and 150mV driving force (=200pS/um2)
	
}


NEURON {
	
	SUFFIX ih
	NONSPECIFIC_CURRENT Ih
	RANGE Ih, gbar
	THREADSAFE
}

STATE {
	
	h
}

ASSIGNED {
	
	Ih (mA/cm2)
}

INITIAL {
	
	h=alpha(v)/(beta(v)+alpha(v))
}

BREAKPOINT {
	
	SOLVE state METHOD cnexp
	Ih = gbar*h*(v-eh)
}

FUNCTION alpha(v(mV)) {
	
	alpha = 0.001*6.43*(v+154.9)/(exp((v+154.9)/11.9)-1)

	: parameters are estimated by direct fitting of HH model to activation time constants and voltage actication curve recorded at 34C by M. Kole
}

FUNCTION beta(v(mV)) {
	
	beta = 0.001*193*exp(v/33.1)
}

DERIVATIVE state {     

	: exact when v held constant; integrates over dt step
	h' = (1-h)*alpha(v) - h*beta(v)
}

Loading data, please wait...