Synchronicity of fast-spiking interneurons balances medium-spiny neurons (Damodaran et al. 2014)

 Download zip file 
Help downloading and running models
This study investigates the role of feedforward and feedback inhibition in maintaining the balance between D1 and D2 MSNs of the striatum. The synchronized firing of FSIs are found to be critical in this mechanism and specifically the gap junction connections between FSIs.
1 . Damodaran S, Evans RC, Blackwell KT (2014) Synchronized firing of fast-spiking interneurons is critical to maintain balanced firing between direct and indirect pathway neurons of the striatum. J Neurophysiol 111:836-48 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism:
Cell Type(s): Neostriatum spiny direct pathway neuron; Neostriatum spiny indirect pathway neuron; Neostriatum fast spiking interneuron;
Gap Junctions: Gap junctions;
Receptor(s): NMDA; Gaba;
Simulation Environment: GENESIS;
Model Concept(s): Detailed Neuronal Models; Parkinson's;
Implementer(s): Blackwell, Avrama [avrama at]; Damodaran, Sriraman [dsriraman at];
Search NeuronDB for information about:  Neostriatum spiny direct pathway neuron; Neostriatum spiny indirect pathway neuron; NMDA; Gaba;
AddCaSpines.g *
addchans.g *
addchans.g~ *
addinput.g *
addoutput.g *
addoutput_old.g *
AddSynapticChannels.g *
connectCaChannels.g *
DA_files.txt *
globalsCaComp.g *
include_channels.g *
MScell.p *
MScell_D1.g *
MScell_D2.g *
MScell08.p *
MScell08CM3_D1.p *
MScell08CM3_D2.p *
MScellSpine.g *
MScellSpineCtx.g *
MScellSpineTh.g *
MScellSyn.g~ *
MScellSyn_D1.g *
MScellSyn_D2.g *
parametersA_D1.g *
parametersA_D2.g *
parametersB.g *
parametersC.g *
parametersD.g *
proto.g *
spines.g *
SynParamsCtx.g *
SynParamsTh.g *

/***************************		MS Model, Version 5.10	**********************
**************************** 	      	globals.g 			**********************
Tom Sheehan	703-538-8361
	The capatilized parameters defined below are global and visable to all files
	Capatilized parameters should be treated as constants
/* AB: Comments indicate the qfactor used with the various channels
*  conductance of CaN and CaL12 sum the inactivating and non-inactivating channel
*  conductances from the previous model
        float ELEAK = -0.070
        float PI = 3.1415926
        float RA = 1.0;
        float RM = 8.69565217;
        float CM = 0.01;
        float EREST_ACT = -0.085
 	float TEMPERATURE = 35
	str  CA_BUFF_1 = "Ca_difshell_1"     // L and T type channels
	str  CA_BUFF_2 = "Ca_difshell_2"     // coupled to the other channels
	str  CA_BUFF_3 = "Ca_difshell_3"     // all calcium channels
	int CaDyeFlag = 0    // flags of calcium dye. "0" means NO calcium dyes.
                     // flag =2 : Fluo-4
                     // flag =3 : Fluo-5F
	int shellMode = 1     // we  have two shell-modes:
                     //  mode = 0 : detailed multi-shell model, using "difshell" object
                     //  mode = 1 : simple calcium pool adopted from  Sabatini's work(Sabatini, 2001, 2004)

//parameters determined by hand tuning to match spike width, AHP shape &amp, fI curve
//spike width with these globals plus spines = 0.88 ms
        str gNaFprox={90000}  //qfactor = 1.2   
        str gNaFmid={2730}
        str gNaFdist={975}

        str gKAfprox={3214}   //qfactor=1.5 for inact
        str gKAfmid={471}     //1/qfactor=1.5 for act!!!
        str gKAfdist={314}

        str gKAsprox={277}    //qfactor=2	 
        str gKAsdist={22.9}

        str gKIR=4.2          //qfactor = 0.5
        str gKDR={7.25}       //qfactor = 0.5  

	float gCaL13 = {1.0625e-7+1.07e-7}  //qfactor=2
	float gCaT  =  {0.5875e-8+0.58e-8}
	float gCaR  =  {6.5e-7+6.43e-7}
//	float gCaQ  =  1.5e-7
	float gCaN =   2.5e-7       //qfactor=2
	float gCaL12 = {0.8375e-7+0.83e-7}    //qfactor=2

/* Surface area of spine head = 7.853981593e-13m^2, 165 spines (205 total comps)
   gCaR = 13e-7 -> 1.021017568e-18 /spine -> 1.6838e-16 total
   gCaT = 0.235e-7 -> 1.845685677e-20 /spine -> 3.0454e-18 total
   gCaL12 = 3.35e-7 -> 2.631083943e-19 /spine -> 4.34e-17 total
   gCaL13 = 4.25e-7 -> 3.337942088e-19 /spine -> 5.5075e-17 total
conductance of channels in soma (SA=8e-10), primdend1 (1.4e-10), secdend1 (0.84e-10), 
gCaR =   5.227605712e-16 9.189150748e-17 5.44263204e-17 
gCaT =   4.724951198e-18 8.305578876e-19 4.919302039e-19
gCaL12 = 6.735568939e-17 1.183986707e-17 7.012622166e-18
gCaL13 = 8.545124467e-17 1.502072808e-17 8.896610384e-18

If we add 1 spines worth of calcium per compartment, hopefully that will restore activity to the spine state:
increment for no spines (uses 0.9e-10*(165/205), ~0.7, as comp SA:
gCaR 6.43e-7
gCaT 0.58e-8
gCaL12 0.83e-7
gCaL13 1.07e-7
Each spine contributes RM/SA and CM*SA.  Thus, removing the spines requires and increase in CM and decrease in RM to compensate.  But increase should be proportional to relative area of spine head, e.g. ~1e-12 for spine vs 0.84e-10 for secdend, and 0.909e-10 (tert)


Loading data, please wait...