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

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"... 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. …"
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;
Simulation Environment: GENESIS;
Model Concept(s): Oscillations; STDP; Calcium dynamics;
Implementer(s): Evans, Rebekah [Rebekah.Evans at];
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;
str cellpath = "/cell"

include RebekahSims/SpikeMaker.g
include RebekahSims/add_outputgrad


str stimtype = "20Hz5msAP"
echo {diskpath}
setfield /output/plot_out filename output/{diskpath}
call /output/plot_out OUT_OPEN
call /output/plot_out OUT_WRITE "time SomaVm tert1Vm tert5Vm tert9Vm tert13Vm tert1fura tert5fura tert9fura tert13fura tert1vol tert5vol tert9vol tert13vol" //header	

int Hz = 20 //for glu, function multiplies this by 2 for GABA
float upstate_time = 0.3
float AP_time = 0.005  //AP latency from upstate onset
float AP_durtime = 0.002 //duration of AP depolarization at soma, 5 ms
float high_time = 0.01
float med_time  = 0.2
float low_time  = 0.09

// use randomspike to put inputs into NMDA and AMPA receptors 

makeALLpre {Hz}

step 0.05 -time

makeALLpost "high"

	step {AP_time} -time

	setfield {cellpath}/soma inject {2000e-12}

	step {AP_durtime} -time

	setfield {cellpath}/soma inject 0
	step {{high_time}-{AP_time}-{AP_durtime}}

makeALLpost "med"

	step {med_time} -time

makeALLpost "low"

	step {low_time} -time

	step 0.2 -time

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