Low Threshold Calcium Currents in TC cells (Destexhe et al 1998)

 Download zip file   Auto-launch 
Help downloading and running models
Accession:279
In Destexhe, Neubig, Ulrich, and Huguenard (1998) experiments and models examine low threshold calcium current's (IT, or T-current) distribution in thalamocortical (TC) cells. Multicompartmental modeling supports the hypothesis that IT currents have a density at least several fold higher in the dendrites than the soma. The IT current contributes significantly to rebound bursts and is thought to have important network behavior consequences. See the paper for details. See also http://cns.iaf.cnrs-gif.fr Correspondance may be addressed to Alain Destexhe: Destexhe@iaf.cnrs-gif.fr
Reference:
1 . Destexhe A, Neubig M, Ulrich D, Huguenard J (1998) Dendritic low-threshold calcium currents in thalamic relay cells. J Neurosci 18:3574-88 [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): Thalamus geniculate nucleus/lateral principal GLU cell;
Channel(s): I Na,t; I T low threshold; I K;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Dendritic Action Potentials; Bursting; Ion Channel Kinetics; Parameter Fitting; Simplified Models; Influence of Dendritic Geometry; Detailed Neuronal Models; Calcium dynamics; Rebound firing;
Implementer(s): Destexhe, Alain [Destexhe at iaf.cnrs-gif.fr];
Search NeuronDB for information about:  Thalamus geniculate nucleus/lateral principal GLU cell; I Na,t; I T low threshold; I K;
/
dendtc
cells
README
cadecay.mod *
hh2.mod *
ITGHK.mod *
VClamp.mod *
El.oc *
loc200.oc
loc3.oc *
locD.oc
mosinit.hoc *
rundemo.hoc
tc1_cc.oc
tc200_cc.oc
tc200_vc.oc
tc3_cc.oc
tcD_vc.oc
                            
TITLE Fast mechanism for submembranal Ca++ concentration (cai)
:
: Takes into account:
:
:	- increase of cai due to calcium currents
:	- extrusion of calcium with a simple first order equation
:
: This mechanism is compatible with the calcium pump "cad" and has the 
: same name and parameters; however the parameters specific to the pump
: are dummy here.
:
: Parameters:
:
:	- depth: depth of the shell just beneath the membran (in um)
:	- cainf: equilibrium concentration of calcium (2e-4 mM)
:	- taur: time constant of calcium extrusion (must be fast)
:	- kt,kd: dummy parameters
:
: Written by Alain Destexhe, Salk Institute, 1995
:

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

NEURON {
	SUFFIX cad
	USEION ca READ ica, cai WRITE cai
	RANGE depth,kt,kd,cainf,taur
}

UNITS {
	(molar) = (1/liter)			: moles do not appear in units
	(mM)	= (millimolar)
	(um)	= (micron)
	(mA)	= (milliamp)
	(msM)	= (ms mM)
}

CONSTANT {
	FARADAY = 96489		(coul)		: moles do not appear in units
:	FARADAY = 96.489	(k-coul)	: moles do not appear in units
}

PARAMETER {
	depth	= .1	(um)		: depth of shell
	taur	= 5	(ms)		: rate of calcium removal
	cainf	= 2e-4	(mM)
	kt	= 0	(mM/ms)		: dummy
	kd	= 0	(mM)		: dummy
}

STATE {
	cai		(mM) 
}

INITIAL {
	cai = cainf
}

ASSIGNED {
	ica		(mA/cm2)
	drive_channel	(mM/ms)
}
	
BREAKPOINT {
	SOLVE state METHOD derivimplicit
}

DERIVATIVE state { 

	drive_channel =  - (10000) * ica / (2 * FARADAY * depth)

	if (drive_channel <= 0.) { drive_channel = 0. }	: cannot pump inward

	cai' = drive_channel + (cainf-cai)/taur
}


Loading data, please wait...