Thalamic reticular neurons: the role of Ca currents (Destexhe et al 1996)

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Accession:17663
The experiments and modeling reported in this paper show how intrinsic bursting properties of RE cells may be explained by dendritic calcium currents.
Reference:
1 . Destexhe A, Contreras D, Steriade M, Sejnowski TJ, Huguenard JR (1996) In vivo, in vitro, and computational analysis of dendritic calcium currents in thalamic reticular neurons. J Neurosci 16:169-85 [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 reticular nucleus GABA cell;
Channel(s): I Na,t; I T low threshold; I K; I Sodium; I Calcium; I Potassium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Dendritic Action Potentials; Bursting; Simplified Models; Active Dendrites; Influence of Dendritic Geometry; Detailed Neuronal Models; Action Potentials; Calcium dynamics;
Implementer(s): Destexhe, Alain [Destexhe at iaf.cnrs-gif.fr];
Search NeuronDB for information about:  Thalamus reticular nucleus GABA cell; I Na,t; I T low threshold; I K; I Sodium; I Calcium; I Potassium;
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dendre
cells
README
capump.mod *
HH2.mod *
IT2.mod
VClamp.mod *
El.oc *
leak.oc *
loc3.oc *
loc80.oc *
locD.oc *
mosinit.hoc *
re1_cc.oc
re3_cc.oc
re3_vc.oc
re80_cc.oc
re80_vc.oc
reD_cc.oc
reD_vc.oc
rundemo.hoc *
                            
TITLE svclmp.mod

COMMENT

Single electrode Voltage clamp with three levels
------------------------------------------------

Series Resistance added; backards compatible, except parameters 
e0,vo0,vi0,gain,rstim,tau1,tau2 that no longer exist

Clamp is on at time 0, and off at time dur[0]+dur[1]+dur[2]. When clamp is off
the injected current is 0.  The clamp levels are amp[0], amp[1], amp[2].  i is
the injected current, vc measures the control voltage) Do not insert several
instances of this model at the same location in order to make level changes.
That is equivalent to independent clamps and they will have incompatible
internal state values.

The electrical circuit for the clamp is exceedingly simple:

        rs           Rin
vc ---'\/\/`---o---'\/\/`---o
               |            |
               |____| |_____|
                    | |
                     Cm

Note that since this is an electrode current model v refers to the internal
potential which is equivalent to the membrane potential v when there is no
extracellular membrane mechanism present but is v+vext when one is present. 
Also since i is an electrode current, positive values of i depolarize the
cell. (Normally, positive membrane currents are outward and thus hyperpolarize
the cell)

ENDCOMMENT

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

DEFINE NSTEP 3

NEURON {
        POINT_PROCESS SEVClamp
        ELECTRODE_CURRENT i
        RANGE dur, amp, rs, vc, i
}

UNITS {
        (nA) = (nanoamp)
        (mV) = (millivolt)
        (uS) = (micromho)
}


PARAMETER {
        v (mV)
        rs = 1 (megohm)		: series resistance
}

ASSIGNED {
        i (nA)
        vc (mV)
        ic (nA)
        tc2 (ms)
        tc3 (ms)
	dur[NSTEP] (ms)
	amp[NSTEP] (mV)
        on
}

INITIAL {
        tc2 = dur[0] + dur[1]
        tc3 = tc2 + dur[2]
        on = 0
}

BREAKPOINT {
        SOLVE vstim
        if (on) {
                i = (vc - v)/rs
        }else{
                i = 0
        }
}

PROCEDURE vstim() {
        on = 1
        if (t < dur[0]) {
                vc = amp[0]
        }else if (t < tc2) {
                vc = amp[1]
        }else if (t < tc3) {
                vc = amp[2]
        }else {
                vc = 0
                on = 0
        }
        if (on) {
        }else{
                ic = 0
        }
        VERBATIM
        return 0;
        ENDVERBATIM
}

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