L5 PFC microcircuit used to study persistent activity (Papoutsi et al. 2014, 2013)

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Accession:155057
Using a heavily constrained biophysical model of a L5 PFC microcircuit we investigate the mechanisms that underlie persistent activity emergence (ON) and termination (OFF) and search for the minimum network size required for expressing these states within physiological regimes.
References:
1 . Papoutsi A, Sidiropoulou K, Cutsuridis V, Poirazi P (2013) Induction and modulation of persistent activity in a layer V PFC microcircuit model. Front Neural Circuits 7:161 [PubMed]
2 . Papoutsi A, Sidiropoulou K, Poirazi P (2014) Dendritic nonlinearities reduce network size requirements and mediate ON and OFF states of persistent activity in a PFC microcircuit model. PLoS Comput Biol 10:e1003764 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Dendrite; Connectionist Network;
Brain Region(s)/Organism: Neocortex;
Cell Type(s): Neocortex L5/6 pyramidal GLU cell;
Channel(s): I Na,p; I Na,t; I L high threshold; I A; I CAN; I Potassium; I R; I_AHP;
Gap Junctions:
Receptor(s): GabaA; GabaB; AMPA; NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Active Dendrites; Working memory;
Implementer(s): Papoutsi, Athanasia [athpapoutsi at gmail.com];
Search NeuronDB for information about:  Neocortex L5/6 pyramidal GLU cell; GabaA; GabaB; AMPA; NMDA; I Na,p; I Na,t; I L high threshold; I A; I CAN; I Potassium; I R; I_AHP;
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L5microcircuit
mechanism
ampa.mod
ampain.mod
cadyn.mod
cal.mod
can.mod
car.mod
cat.mod
gabaa.mod *
gabaain.mod
gabab.mod
h.mod
ican.mod
iks.mod
kadist.mod
kca.mod
kct.mod
kdr.mod *
naf.mod
nap.mod
netstim.mod *
NMDA.mod
NMDA_syn.mod
sinclamp.mod *
vecstim.mod *
                            
TITLE Ca R-type channel with medium threshold for activation
: used in distal dendritic regions, together with calH.mod, to help
: the generation of Ca++ spikes in these regions
: uses channel conductance (not permeability)
: written by Yiota Poirazi on 11/13/00 poirazi@LNC.usc.edu
:
: updated to use CVode by Carl Gold 08/10/03
: Updated by Maria Markaki  03/12/03
: changed on july 13, 2007 by Sidiropoulou

NEURON {
	SUFFIX car
	USEION ca READ cai, cao WRITE ica
        RANGE gcabar, m, h,ica
	RANGE inf, fac, tau
}

UNITS {
	(mA) = (milliamp)
	(mV) = (millivolt)
	(molar) = (1/liter)
	(mM) =	(millimolar)
	FARADAY = (faraday) (coulomb)
	R = (k-mole) (joule/degC)
}


ASSIGNED {               : parameters needed to solve DE
	ica (mA/cm2)
        inf[2]
	tau[2]		(ms)
        v               (mV)
        celsius 	(degC)
	ecar    	(mV)      
	cai             (mM)      : initial internal Ca++ concentration
	cao             (mM)      : initial external Ca++ concentration
}


PARAMETER {              : parameters that can be entered when function is called in cell-setup
        gcabar = 0      (mho/cm2) : initialized conductance
}  

STATE {	
	m 
	h 
}            : unknown activation and inactivation parameters to be solved in the DEs  


INITIAL {
	rates(v)
        m = 0    : initial activation parameter value
	h = 1    : initial inactivation parameter value
}

BREAKPOINT {
	SOLVE states METHOD cnexp
	ecar = (1e3) * (R*(celsius+273.15))/(2*FARADAY) * log (cao/cai)
	ica = gcabar*m*m*m*h*(v - ecar)
:	iCa = gcabar*m*m*m*h*(v - ecar)

}


DERIVATIVE states {
	rates(v)
	m' = (inf[0]-m)/tau[0]
	h' = (inf[1]-h)/tau[1]
}

PROCEDURE rates(v(mV)) {LOCAL a, b :rest = -70
	FROM i=0 TO 1 {
		tau[i] = vartau(v,i)
		inf[i] = varss(v,i)
	}
}




FUNCTION varss(v(mV), i) {
	if (i==0) {

	   varss = 1 / (1 + exp((v+43.5)/(-3(mV)))) : Ca activation original
	}
	else if (i==1) {
           
	     varss = 1/ (1 + exp((v+50)/(1(mV))))    : Ca inactivation original
	}
}

FUNCTION vartau(v(mV), i) (ms){
	if (i==0) {
           vartau = 70(ms)  : activation variable time constant
        }
	else if (i==1) {
           vartau = 20(ms)   : inactivation variable time constant
       }
	
}	















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