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

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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]
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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;
//genesis


/***************************		MS Model, Version 8	*********************
**************************** 	      MScellqfact.g 	*********************
	Avrama Blackwell 	kblackw1@gmu.edu
	Wonryull Koh		wkoh1@gmu.edu
	Rebekah Evans 		rcolema2@gmu.edu
	Sriram 			dsriraman@gmail.com	
******************************************************************************

*****************************************************************************
*************************
	MS_cell.g has only one externally called function: make_MS_cell. That primary 
	function uses the services of the following two local subroutines:
		set_position
		add_channels

******************************************************************************/

include MScell/globals  		// Defines & initializes cell specific parameters
include MScell/Ca_constants.g
include MScell/proto  // provides access to make_prototypes (and individual channels) 
include MScell/addchans	// provides access to add_uniform_channel & add_CaShells 
include MScell/CaDifshell.g
        
    	
//************************ Begin Local Subroutines ****************************
//*****************************************************************************

	//************************ Begin function set_position *********************
	//**************************************************************************
	function set_position (cellpath)
		//********************* Begin Local Variables ************************
 		str compt, cellpath
 		float dist2soma,x,y,z
 		//********************* End Local Variables *****************************
 		
 		if (!{exists {cellpath}})
  			echo The current input {cellpath} does not exist (set_position) 
  			return
 		end
 
 		foreach compt ({el {cellpath}/##[TYPE=compartment]})
     		  x={getfield {compt} x}
     		  y={getfield {compt} y}
     		  z={getfield {compt} z}
     		  dist2soma={sqrt {({pow {x} 2 }) + ({pow {y} 2}) + ({pow {z} 2})} }  
     		  setfield {compt} position {dist2soma}
   	        end
	end
	//************************ End function set_position ***********************
	//**************************************************************************

	//************************ Begin function add_channels *********************
	//**************************************************************************
	function add_channels (cellpath)
         str cellpath
	
		/* add_uniform_channel (from addchans.g)
					channel_Name	a    		b 	density	  channeltype - VC for calcium permeable, KC for calcium dep*/

		// Naf in the soma 
		add_uniform_channel "NaF_channel"   0      {somaLen}	{gNaFsoma} {cellpath} "V"
		// Naf in the dendrites
		add_uniform_channel "NaFd_channel"   {somaLen} {mid} 	{gNaFprox}  {cellpath} "V"
		add_uniform_channel "NaFd_channel"   {mid}  {dist} 	{gNaFdist}  {cellpath} "V"  

		// potassium channels
		add_uniform_channel "KAf_channel"   0      {somaLen}	{gKAfsoma} {cellpath} "V"
		add_uniform_channel "KAf_channel"   {somaLen} {dist}	{gKAfdend}   {cellpath} "V"  
		
		add_uniform_channel "KAs_channel"  0       {somaLen}	{gKAssoma} {cellpath}  "V" 
		add_uniform_channel "KAs_channel"  {somaLen}  {dist} 	{gKAsdend} {cellpath} "V"
    
		
		//note that these two channels don't have distance dependent  conductances
		add_uniform_channel "KIR_channel"   0        {somaLen}	 {gKIRsoma}  {cellpath} "V"
		add_uniform_channel "KIR_channel"   {somaLen}  {dist}	 {gKIRdend}  {cellpath} "V"

  		add_uniform_channel "Krp_channel"    0        {somaLen}     {gKrpsoma}  {cellpath} "V"
		add_uniform_channel "Krp_channel"    {somaLen}  {dist}     {gKrpdend}  {cellpath} "V"

		
 echo "add VGCC"
		add_uniform_channel "CaR_channel" 		0 	{somaLen}  {gCaRsoma} {cellpath} "VC"
		add_uniform_channel "CaR_channel" 		{somaLen} 	{dist}  {gCaRdend} {cellpath} "VC"
 
		add_uniform_channel "CaN_channel" 		0 	{somaLen}  {gCaNsoma}  {cellpath} "VC"
		
		add_uniform_channel "CaL12_channel"     0 	{somaLen}  {gCaL12soma}  {cellpath} "VC"
		add_uniform_channel "CaL12_channel"     {somaLen} 	{dist}  {gCaL12dend}  {cellpath} "VC"
		
		add_uniform_channel "CaL13_channel" 	0 		{somaLen}  {gCaL13soma} {cellpath} "VC"
		add_uniform_channel "CaL13_channel" 	{somaLen} 	{mid}  {gCaL13dend} {cellpath} "VC"
		add_uniform_channel "CaL13_channel" 	{mid} 	{dist}  {gCaL13dend} {cellpath} "VC"
		
		add_uniform_channel "CaT_channel" 	{prox} 	{dist}  {gCaTdist} {cellpath} "VC"

echo "add KCa"
		add_uniform_channel "BK_channel" 		0 	{somaLen}	{gBKsoma} {cellpath} "KC"  
		add_uniform_channel "BK_channel" 		{somaLen}	{dist}	{gBKdend} {cellpath} "KC"  

		add_uniform_channel "SK_channel" 		0 	{somaLen} {gSKsoma} {cellpath} "KC"
		add_uniform_channel "SK_channel" 		{somaLen} 	{dist}  {gSKdend} {cellpath} "KC"

	end

 
	//************************ End function add_channels ***********************
	//**************************************************************************
//************************ End Local Subroutines ******************************
//*****************************************************************************

//************************ Begin Primary Routine ******************************
//*****************************************************************************

	//************************ Begin function make_MS_cell *********************
	//**************************************************************************
	function make_MS_cell (cellpath,pfile)
         str cellpath,pfile
         echo {cellpath}
 	// function make_MS_cell is the first call from the primary file (MSsim.g). 
	// Note that the first thing it does is to call make_protypes in proto.g. 
	// These prototypes must be made before the call to add_channels. 

		make_prototypes					//	see proto.g
//		readcell {pfile} {cellpath} -hsolve	//	see MScell.g
              readcell {pfile} {cellpath}
		set_position {cellpath}					// local call
//allow either the full calcium dynamics or the old single time constant of decay
        if (calciumtype==0)
		    add_caconcen_objects {CalciumName} {cellpath}
		    //make_extra_pools 0 500e-6 {cellpath} 
        else 
		// to be coupled with N/R Ca2+ channels 
            add_CaConcen {CA_BUFF_1}  0 500e-6   {cellpath} 
		// to be coupled with T/L Ca2+ channels 
            add_CaConcen {CA_BUFF_2}  0 500e-6  {cellpath} 
		// to be coupled with all Ca2+ channels    
            add_CaConcen {CA_BUFF_3}  0 500e-6   {cellpath}
        end

        echo "finished adding calcium"
		add_channels {cellpath}					// local call
		//SumGk {cellpath}/tertdend1_1  //SumGk in addchans.g
		//SumCa {cellpath}/tertdend1_1 //SumCa in addchans.g
	end	
	//************************ End function make_MS_cell ***********************
	//**************************************************************************			
//************************ End Primary Routine ********************************
//*****************************************************************************