Calcium influx during striatal upstates (Evans et al. 2013)

 Download zip file 
Help downloading and running models
Accession:150912
"... To investigate the mechanisms that underlie the relationship between calcium and AP timing, we have developed a realistic biophysical model of a medium spiny neuron (MSN). ... Using this model, we found that either the slow inactivation of dendritic sodium channels (NaSI) or the calcium inactivation of voltage-gated calcium channels (CDI) can cause high calcium corresponding to early APs and lower calcium corresponding to later APs. We found that only CDI can account for the experimental observation that sensitivity to AP timing is dependent on NMDA receptors. Additional simulations demonstrated a mechanism by which MSNs can dynamically modulate their sensitivity to AP timing and show that sensitivity to specifically timed pre- and postsynaptic pairings (as in spike timing-dependent plasticity protocols) is altered by the timing of the pairing within the upstate. …"
Reference:
1 . Evans RC, Maniar YM, Blackwell KT (2013) Dynamic modulation of spike timing-dependent calcium influx during corticostriatal upstates. J Neurophysiol 110:1631-45 [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: Striatum;
Cell Type(s): Neostriatum medium spiny direct pathway GABA cell;
Channel(s): I Na,t; I L high threshold; I N; I A; I K; I K,Ca; I A, slow; I Krp; I R;
Gap Junctions:
Receptor(s): AMPA; NMDA; Gaba;
Gene(s): Cav1.3 CACNA1D; Cav1.2 CACNA1C; Cav2.2 CACNA1B;
Transmitter(s):
Simulation Environment: GENESIS;
Model Concept(s): Oscillations; STDP; Calcium dynamics;
Implementer(s): Evans, Rebekah [Rebekah.Evans at nih.gov];
Search NeuronDB for information about:  Neostriatum medium spiny direct pathway GABA cell; AMPA; NMDA; Gaba; I Na,t; I L high threshold; I N; I A; I K; I K,Ca; I A, slow; I Krp; I R;
/
EvansEtAl2013
MScell
channels
ampa_channel.g
BK.g *
CaL12CDI.g
CaL13CDI.g
CaN.g
CaNCDI.g
CaR.g
CaRCDI.g
CaT.g *
gaba_channel.g *
KaF.g *
KaFnew.g *
KaS.g
Kir.g *
Krp.g
NaF.g *
NaFslowinact.g *
nmda_channel.g
SK.g *
synaptic_channel.g
tabchanforms.g *
                            
//genesis

/***************************		MS Model, Version 9.1	*********************
**************************** 	  		CaR.g 			*********************
	Rebekah Evans 3/20/12 updated channel. 
******************************************************************************
******************************************************************************/

function create_CaR
	str chanName = "CaR_channel"
	str compPath = "/library"

	int c = 0	

	int xdivs = 3000
	float Ek = 0.140  //(nernst calculated for 35degrees, [Cain] 50nM [Caout]2mM)
			//Ek is overwritten the the GHK object if it is used. 
	float x = -0.1
	float xmin = -0.1
	float xmax = 0.05
        float increment ={{xmax}-{xmin}}/{xdivs}
        echo "CaR increment:" {increment} "V"
  	float mPower = 3.0  //Foerhing et al., 2000 p 2228
  	float hPower = 1.0

	float mvHalfCaR = -29e-3  
	float mkCaR     = -9.6e-3
	float hvHalfCaR = -33.3e-3
	float hkCaR     = 17e-3

	float mTauCaR = 5.1e-003  //Foehring et al., 2000 pg 2230.
	float mInfCaR = 0.0
	float hTauCaR = 0.0
	float hInfCaR = 0.0
	float hA 
	float hB

	float qFactCaR = {qfactCa}

	float surf = 0.0
	float gMax = 0

	float theta = 0.0
	float theta_exp = 0.0

	float beta = 0.0
	float beta_exp = 0.0

	create tabchannel {chanName}
  	setfield {chanName} Ek {Ek} Xpower {mPower} Ypower {hPower}
	call {chanName} TABCREATE X {xdivs} {xmin} {xmax}
   call {chanName} TABCREATE Y {xdivs} {xmin} {xmax}

	for(c = 0; c < {xdivs} + 1; c = c + 1)
		/************************ Begin CaR_mTau *********************/
		// mTauCaR 
		setfield {chanName} X_A->table[{c}] {{mTauCaR}/{qFactCaR}}
		/************************ End CaR_mTau ***********************/
		
		/************************ Begin CaR_mInf *********************/
		//mInfCaR   = 1./(1 + exp((vMemb - mvHalfCaR)/mkCaR));
		// parameters tuned to fit Foerhing et al., 2000 fig 6
		theta = {{x} - {mvHalfCaR}}/{mkCaR}
		theta_exp = {exp {theta}} + 1.0
		mInfCaR = 1.0/{theta_exp}
		setfield {chanName} X_B->table[{c}] {mInfCaR}
		/************************ End CaR_mInf ***********************/

	
		/************************ Begin CaR_hTau *********************/
		// hA = 10e6*(vMemb + 0.0945)./
		//                      (exp((vMemb + 0.0945)/0.00512)-1);
		// hB = 84.2*exp(vMemb/0.013);
		// hTauCaR = ((1/(hA + hB))+0.1) / qFactCaR;
		// parameters tuned to fit Brevi 2001 fig 10


		theta = {{10e6}*{ {x} + 0.0945}}
		beta = {{x}  + 0.0945}/0.00512
		beta_exp = {exp {beta}}
		beta_exp = beta_exp - 1.0
		hA = {{theta}/{beta_exp}}

		beta = {{x}/0.013}
		beta_exp = {exp {beta}} 
		hB = 84.2*{beta_exp}

		hTauCaR = {{1.0/{{hA} + {hB}}}+0.02}		
		setfield {chanName} Y_A->table[{c}] {hTauCaR}/{qFactCaR}
		/************************ End CaR_hTau ***********************/
		
		/************************ Begin CaR_hInf *********************/
		//hInfCaR   = 1./(1 + exp((vMemb - hvHalfCaR)/hkCaR));
		// parameters tuned to fit Foerhing et al., 2000 fig 7
		theta = {{x} - {hvHalfCaR}}/{hkCaR}
		theta_exp = {exp {theta}} + 1.0
		hInfCaR = 1.0/{theta_exp}
		setfield {chanName} Y_B->table[{c}] {hInfCaR}
		/************************ End CaR_hInf ***********************/
    	x = x + increment
	end

	tweaktau {chanName} X
	tweaktau {chanName} Y

  	create ghk {chanName}GHK

  	setfield {chanName}GHK Cout 2 // Carter & Sabatini 2004 uses 2mM, 
											// Wolf 5mM
  	setfield {chanName}GHK valency 2.0
  	setfield {chanName}GHK T {TEMPERATURE}
	
  	setfield {chanName} Gbar {gMax*surf}
  	addmsg {chanName} {chanName}GHK PERMEABILITY Gk	
  	
end



Loading data, please wait...