Effects of spinal cord stimulation on WDR dorsal horn network (Zhang et al 2014)

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Accession:168414
" ... To study the mechanisms underlying SCS (Spinal cord stimulation), we constructed a biophysically-based network model of the dorsal horn circuit consisting of interconnected dorsal horn interneurons and a wide dynamic range (WDR) projection neuron and representations of both local and surround receptive field inhibition. We validated the network model by reproducing cellular and network responses relevant to pain processing including wind-up, A-fiber mediated inhibition, and surround receptive field inhibition. ..." See paper for more.
Reference:
1 . Zhang TC, Janik JJ, Grill WM (2014) Modeling effects of spinal cord stimulation on wide-dynamic range dorsal horn neurons: influence of stimulation frequency and GABAergic inhibition. J Neurophysiol 112:552-67 [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): Wide dynamic range neuron;
Channel(s):
Gap Junctions:
Receptor(s): GabaA; AMPA; NMDA; Glutamate; Glycine;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s):
Implementer(s): Zhang, Tianhe [tz5@duke.edu];
Search NeuronDB for information about:  GabaA; AMPA; NMDA; Glutamate; Glycine;
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ZhangEtAl2014
Critical Mod Files
AMPA_DynSyn.mod
B_A.mod
B_DR.mod
B_NA.mod
CaIntraCellDyn.mod *
GABAa_DynSyn.mod *
GABAb_DynSyn.mod *
Glycine_DynSyn.mod
HH2.mod *
HH2new.mod *
iCaAN.mod *
iCaL.mod
iKCa.mod *
iNaP.mod *
KDR.mod
KDRI.mod
NK1_DynSyn.mod *
NMDA_DynSyn.mod *
SS.mod
vsource.mod *
                            
TITLE  NMDA receptor with Ca influx and pre-synaptic short-term plasticity


COMMENT
Dynamic presynaptic activity based on Fuhrmann et al, 2002: "Coding of temporal information by activity-dependent synapses" 

Written by Paulo Aguiar and Mafalda Sousa, IBMC, May 2008
pauloaguiar@fc.up.pt ; mafsousa@ibmc.up.pt
ENDCOMMENT


NEURON {
	POINT_PROCESS NMDA_DynSyn
	USEION ca WRITE ica	
	USEION mg READ mgo VALENCE 2
	RANGE tau_rise, tau_decay
	RANGE U1, tau_rec, tau_fac
	RANGE i, g, e, mg, inon, ica, ca_ratio
	NONSPECIFIC_CURRENT inon
    }
    
UNITS {
	(nA) = (nanoamp)
	(mV) = (millivolt)
	(molar) = (1/liter)
	(mM) = (millimolar)
    }    
    
    PARAMETER {
  	tau_rise  = 5.0   (ms)  : dual-exponential conductance profile
	tau_decay = 70.0  (ms)  : IMPORTANT: tau_rise < tau_decay
	U1        = 1.0   (1)   : The parameter U1, tau_rec and tau_fac define
	tau_rec   = 0.1   (ms)  : the pre-synaptic SP short-term plasticity
	tau_fac   = 0.1   (ms)  : mechanism (see Fuhrmann et al, 2002)
	e         = 0.0   (mV)  : synapse reversal potential
	mgo		  = 1.0   (mM)  : external magnesium concentration
	ca_ratio  = 0.1   (1)   : ratio of calcium current to total current( Burnashev/Sakmann J Phys 1995 485 403-418)
    }
    
    
ASSIGNED {
	v		(mV)
	i		(nA)
	g		(umho)
	factor	(1)
	ica		(nA)
	inon	(nA)
}

STATE {
	A
	B
}

INITIAL{
	LOCAL tp
	A = 0
	B = 0
	tp = (tau_rise*tau_decay)/(tau_decay-tau_rise)*log(tau_decay/tau_rise)
	factor = -exp(-tp/tau_rise)+exp(-tp/tau_decay)
	factor = 1/factor
}

BREAKPOINT {
	SOLVE state METHOD cnexp
	g = B-A
	i = g*mgblock(v)*(v-e)
	ica = ca_ratio*i
	inon = (1-ca_ratio)*i
	:printf("\nt=%f\tinon=%f\tica=%f\ti=%f\tmgb=%f",t, inon, ica, i, mgblock(v))
}

DERIVATIVE state{
	A' = -A/tau_rise
	B' = -B/tau_decay
}

FUNCTION mgblock(v(mV)) {
	: from Jahr & Stevens 1990
	mgblock = 1 / (1 + exp(0.062 (/mV) * -v) * (mgo / 3.57 (mM)))
}

NET_RECEIVE (weight, Pv, P, Use, t0 (ms)){
	INITIAL{
		P=1
		Use=0
		t0=t
	}	

	Use = Use * exp(-(t-t0)/tau_fac)
	Use = Use + U1*(1-Use) 
	P = 1-(1- P) * exp(-(t-t0)/tau_rec)
	Pv= Use * P
	P = P - Use * P
	
	t0=t
	
	A=A + weight*factor*Pv
	B=B + weight*factor*Pv
}


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