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 Slow Ca-dependent cation current
                             :
                             :   Ca++ dependent nonspecific cation current ICAN
                             :   Differential equations
                             :
                             :   Model based on a first order kinetic scheme
                             :
                             :       + n cai <->     (alpha,beta)
                             :
                             :   Following this model, the activation fct will be half-activated at 
                             :   a concentration of Cai = (beta/alpha)^(1/n) = cac (parameter)
                             :
                             :   The mod file is here written for the case n=2 (2 binding sites)
                             :   ---------------------------------------------
                             :
                             :   Kinetics based on: Partridge & Swandulla, TINS 11: 69-72, 1988.
                             :
                             :   This current has the following properties:
                             :      - inward current (non specific for cations Na, K, Ca, ...)
                             :      - activated by intracellular calcium
                             :      - NOT voltage dependent
                             :
                             :   A minimal value for the time constant has been added
                             :
                             :   Ref: Destexhe et al., J. Neurophysiology 72: 803-818, 1994.
                             :   See also:  http://www.cnl.salk.edu/~alain , http://cns.fmed.ulaval.ca
                             :

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

                             NEURON {
                                     SUFFIX ican
                                     USEION n READ en WRITE in VALENCE 1
                                     USEION ca READ cai
				     USEION na WRITE ina
                                     RANGE gbar, m_inf, tau_m, in, mystart
                                     GLOBAL beta, cac, taumin 
                             }


                             UNITS {
                                     (mA) = (milliamp)
                                     (mV) = (millivolt)
                                     (molar) = (1/liter)
                                     (mM) = (millimolar)
                             }


                             PARAMETER {
                            	v               (mV)
                              	celsius	= 36    (degC)
                              	en      = -20   (mV)            	: reversal potential
                               	cai     	(mM)           		: initial [Ca]i
                               	gbar    = 0.00025(mho/cm2)
                               	beta 	= 0.00015                     	
                              	cac	= 0.0001			
                              	taumin  = 0.1   (ms)            	: minimal value of time constant
				mystart	= 0 (ms)
                             }


                             STATE {
                                     m
                             }

                             ASSIGNED {
                                     in      (mA/cm2)
				     ina     (mA/cm2)
                                     m_inf
                                     tau_m   (ms)
                                     tadj
                             }

                             BREAKPOINT { 
				if (t>mystart)  { 
                                     SOLVE states METHOD euler
                                     in = gbar * m*m * (v - en)
				     ina = 0.7* in }
                             }

                             DERIVATIVE states { 
                                     evaluate_fct(v,cai)

                                     m' = (m_inf - m) / tau_m
                             }

                             UNITSOFF
                             INITIAL {
                             :
                             :  activation kinetics are assumed to be at 22 deg. C
                             :  Q10 is assumed to be 3
                             :
                                     tadj = 3 ^ ((celsius-22.0)/10)   

                                     evaluate_fct(v,cai)
                                     m = m_inf
                             }


                             PROCEDURE evaluate_fct(v(mV),cai(mM)) {  LOCAL alpha2

                                     alpha2 = beta * (cai/cac)^2

                                     tau_m = 1 / (alpha2 + beta) / tadj
                                     m_inf = alpha2 / (alpha2 + beta)

                                     if(tau_m < taumin) { tau_m = taumin }   : min value of time cst
                             }
                             UNITSON

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