Striatal Spiny Projection Neuron, inhibition enhances spatial specificity (Dorman et al 2018)

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We use a computational model of a striatal spiny projection neuron to investigate dendritic spine calcium dynamics in response to spatiotemporal patterns of synaptic inputs. We show that spine calcium elevation is stimulus-specific, with supralinear calcium elevation in cooperatively stimulated spines. Intermediate calcium elevation occurs in neighboring non-stimulated dendritic spines, predicting heterosynaptic effects. Inhibitory synaptic inputs enhance the difference between peak calcium in stimulated spines, and peak calcium in non-stimulated spines, thereby enhancing stimulus specificity.
1 . Dorman DB, Jedrzejewska-Szmek J, Blackwell KT (2018) Inhibition enhances spatially-specific calcium encoding of synaptic input patterns in a biologically constrained model. Elife, Kennedy, Mary B, ed. [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: Basal ganglia;
Cell Type(s): Neostriatum spiny neuron;
Channel(s): Ca pump; Kir; I A; I A, slow; I CAN; I K,Ca; I Krp; I Na,t; I L high threshold; I R; I T low threshold; IK Bkca; IK Skca; Na/Ca exchanger;
Gap Junctions:
Receptor(s): AMPA; NMDA; GabaA;
Gene(s): Cav3.2 CACNA1H; Cav3.3 CACNA1I; Cav1.2 CACNA1C; Cav1.3 CACNA1D; Cav2.2 CACNA1B; Kv4.2 KCND2; Kir2.1 KCNJ2; Kv2.1 KCNB1;
Transmitter(s): Gaba; Glutamate;
Simulation Environment: GENESIS;
Model Concept(s): Calcium dynamics; Detailed Neuronal Models; Synaptic Integration; Synaptic Plasticity;
Implementer(s): Dorman, Daniel B ;
Search NeuronDB for information about:  GabaA; AMPA; NMDA; I Na,t; I L high threshold; I T low threshold; I A; I K,Ca; I CAN; I A, slow; Na/Ca exchanger; I Krp; I R; Ca pump; Kir; IK Bkca; IK Skca; Gaba; Glutamate;
//Figure out how these different random spikes were used.  May be possible to create them one at a time, or only use one, and change its rate

function UpState(AP_time,AP_durtime,inj,upstate_time, seedval, file)
    float AP_time,AP_durtime,inj,upstate_time
    int seedval
    str file

    int TDstart=1
    int TDsegstart=1
    randseed {seedval}
    int maxRanSpikes, i

    float third_time = {upstate_time}-{first_time}-{second_time}
    //**********set the filenames
    if ({inj}==0)
         str filenam={file}@"Up_"@{Rate1}@"_"@{Rate2}@"_"@{Rate3}@"_noAP"
        str filenam={file}@"Up_"@{Rate1}@"_"@{Rate2}@"_"@{Rate3}@"_AP"@{AP_time}
    echo "################ simulating Upstate, Rates" {Rate1} {Rate2} {Rate3} "AP: " {AP_time} "Inj: " {inj*1e-9}

    setfilename {Vmfile} {filenam} 1 {Vmhead}
    setfilename {Cafile} {filenam} 1 {Cahead}
    setfilename {Gkfile} {filenam} 1 {Gkhead}
    setfilename {spinefile} {filenam} 1 {spinehead}
    //**********create pulse generator for current injection
    float basal_current = 0
    str injectName="/injectCurr"
    createPulseGen {inj} {basal_current} {AP_time+0.05} {AP_durtime} {neuronname}/soma {injectName} 0 "no message"

    //*********create randomspikes for synaptic input
    //0 goes to GABA, should be higher than GLU basal rate
    //1, and optionally 2 & 3 go to GLU.  2&3 are the higher initial rates for gradient
    makeALLspikes {GabaRate} 0 {neuronname} 1 1
    makeALLspikes {Rate1} 1 {neuronname} {TDstart} {TDsegstart}

    if ({first_time} < {upstate_time})
        makeALLspikes {Rate2} 2 {neuronname} {TDstart} {TDsegstart}
        makeALLspikes {Rate3} 3 {neuronname} {TDstart} {TDsegstart}

    //Now run the simulations
    step 0.05 -time

    ConnectALLInput 0 {neuronname} 1 1
    ConnectALLInput 1 {neuronname}  {TDstart} {TDsegstart}
    step {first_time} -time
    DisconnectALLinput 1 {neuronname} {TDstart} {TDsegstart}

    if ({first_time} < {upstate_time})
        ConnectALLInput 2 {neuronname} {TDstart} {TDsegstart}
        step {second_time} -time
        DisconnectALLinput 2 {neuronname} {TDstart} {TDsegstart}

        ConnectALLInput 3 {neuronname} {TDstart} {TDsegstart}
        step {third_time}
        DisconnectALLinput 3 {neuronname} {TDstart} {TDsegstart}
    DisconnectALLinput 0 {neuronname} 1 1
    step 0.2 -t
    for (i=0; i<maxRanSpikes; i=i+1)
        deleteALLspikes {i} {neuronname} {TDstart} {TDsegstart}
    fileFLUSH {Vmfile} 
    fileFLUSH {Cafile} 
    fileFLUSH {Gkfile} 
    fileFLUSH {spinefile}

    setfield {injectName} level1 0


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