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

 Download zip file 
Help downloading and running models
Accession:156260
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.
Reference:
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 medium spiny direct pathway neuron; Neostriatum medium spiny indirect pathway neuron; Neostriatum fast spiking interneuron;
Channel(s):
Gap Junctions: Gap junctions;
Receptor(s): NMDA; Gaba;
Gene(s):
Transmitter(s):
Simulation Environment: GENESIS;
Model Concept(s): Detailed Neuronal Models; Parkinson's;
Implementer(s): Blackwell, Avrama [avrama at gmu.edu]; Damodaran, Sriraman [dsriraman at gmail.com];
Search NeuronDB for information about:  Neostriatum medium spiny direct pathway neuron; Neostriatum medium spiny indirect pathway neuron; NMDA; Gaba;
/
striatalnetwork
Conditions
No_Gaps
FScell
channels
a_channel.g *
ampa_channel.g *
ampa_channel.g~ *
gaba_channel.g *
gaba_channel.g~ *
k13_channel.g *
k3132_channel.g *
na_channel.g *
synaptic_channel.g *
                            
/* describes the activation function for the A channel. 
 * taken from the MSN activation boltzman from:
 * (tkatch, j. neuroscience, 20(2):579-588)
 */

//float EREST_ACT = -0.056
function AChanAct(voltage)

    float voltage
    float vh = -0.045
    float vc = -0.013

  float act = {1 / {1 + {exp {{{voltage}  - {vh}} / {vc}}}}}

    return act
end

/* describes the time constant over a range of voltages
 * taken from Figure 2b of J. neuroscience 20(2):579-588,
 * tkatch january 2000
 */
function AChanTauAct(voltage) 
    float voltage
    float vh = -0.07
    float vc = 0.013
    return {1e-3 * {1 + {exp {-{{voltage} - {vh} } / {vc}}}}}
end

/* describes the inactivation function for the A channel.
 * taken from the MSN inactivation boltzman from:
 * (tkatch, j. neuroscience, 20(2):579-588)
 * vc was not given in this paper, so it was estimated to be
 * about 8mV (see (surmeier, brain research, 473:187-192
 * vh = -0.0756 vc = 0.008
 */
function AChanInact(voltage)

    float voltage
    float vh = -0.077
    float vc =-0.008
    return {1 / {1 + {exp {-{{voltage} - {vh}} / {vc}}}}}

end

/* (tkatch, j. neuroscience, 20(2):579-588)
 * time constant of inactivation of the A channel
 * it is a constant, but the function is placed here in 
 * order to be consistent
 */
function AChanTauInact(voltage) 

    float voltage

    return 0.014

end

function make_A_channel 

    str path = "A_channel"  

    float Erev = -0.09  /* reversal potential of potassium */
    float xmin = -0.1   /* minimum voltage we will see in the simulation */
    float xmax = 0.05   /* maximum voltage we will see in the simulation */
    float step = 0.005  /* use a 5mV step size */
    int xdivs = 30      /* the number of divisions between -0.1 and 0.05 */
    int c = 0

    create tabchannel {path}

    /* make the table for the activation with a range of -100mV - +50mV
     * with an entry for ever 5mV
     */
    call {path} TABCREATE X {xdivs} {xmin} {xmax}
    call {path} TABCREATE Y {xdivs} {xmin} {xmax}

    /* set the tau and m_inf for the activation and inactivation */
    for(c = 0; c <= {xdivs}; c = c + 1)
        setfield {path} X_A->table[{c}] {AChanTauAct {{c * {step}} + xmin}}
        setfield {path} X_B->table[{c}] {AChanAct {{c * {step}} + xmin}}
        setfield {path} Y_A->table[{c}] {AChanTauInact {{c * {step}} + xmin}}
        setfield {path} Y_B->table[{c}] {AChanInact {{c * {step}} + xmin}}
    end

    /* this is fudged from the genesis book */
    setfield {path} Ek {Erev} Xpower 4 Ypower 1
    
    /* fill the tables with the values of A and B
     * calculated from tau and m_inf
     */

/* for testing */
//for(c = 0; c < 30; c = c + 1)  
//        showfield A_channel X_A->table[{c}] 
//        showfield {path} X_B->table[{c}] 
//        showfield {path} Y_A->table[{c}] 
//        showfield {path} Y_B->table[{c}] 
//    end

    tweaktau {path} X
    tweaktau {path} Y


    call {path} TABFILL X 3000 0
    call {path} TABFILL Y 3000 0
end










Loading data, please wait...