Nonlinear dendritic processing in barrel cortex spiny stellate neurons (Lavzin et al. 2012)

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Accession:146565
This is a multi-compartmental simulation of a spiny stellate neuron which is stimulated by a thalamocortical (TC) and cortico-cortical (CC) inputs. No other cells are explicitly modeled; the presynaptic network activation is represented by the number of active synapses. Preferred and non –preferred thalamic directions thus correspond to larder/smaller number of TC synapses. This simulation revealed that randomly activated synapses can cooperatively trigger global NMDA spikes, which involve participation of most of the dendritic tree. Surprisingly, we found that although the voltage profile of the cell was uniform, the calcium influx was restricted to ‘hot spots’ which correspond to synaptic clusters or large conductance synapses
Reference:
1 . Lavzin M, Rapoport S, Polsky A, Garion L, Schiller J (2012) Nonlinear dendritic processing determines angular tuning of barrel cortex neurons in vivo. Nature 490:397-401 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network; Neuron or other electrically excitable cell; Synapse; Dendrite;
Brain Region(s)/Organism:
Cell Type(s): Neocortex spiny stellate cell;
Channel(s): I Sodium; I Potassium; Ca pump;
Gap Junctions:
Receptor(s): GabaA; AMPA; NMDA;
Gene(s):
Transmitter(s): Gaba; Glutamate;
Simulation Environment: NEURON;
Model Concept(s): Active Dendrites; Detailed Neuronal Models; Synaptic Integration; Calcium dynamics; Direction Selectivity; Whisking;
Implementer(s): Polsky, Alon [alonpol at tx.technion.ac.il];
Search NeuronDB for information about:  GabaA; AMPA; NMDA; I Sodium; I Potassium; Ca pump; Gaba; Glutamate; 
COMMENT
//****************************//
// Created by Alon Polsky 	//
//    apmega@yahoo.com		//
//		2007			//
//****************************//
ENDCOMMENT

TITLE AMPA synapse 

NEURON {
	POINT_PROCESS ampa
	
	NONSPECIFIC_CURRENT iampa

	RANGE e ,gmax,ntar,local_v,iampa,gh
	RANGE del,Tspike,Nspike
	RANGE gampa
	GLOBAL tau_ampa
}

UNITS {
	(nA) 	= (nanoamp)
	(mV)	= (millivolt)
	(nS) 	= (nanomho)
	(mM)    = (milli/liter)
        F	= 96480 (coul)
        R       = 8.314 (volt-coul/degC)

}

PARAMETER {
	gmax=1	(nS)
	e= 0.0	(mV)
	tau_ampa=2	(ms)	

	dt (ms)
	v		(mV)
	del=30	(ms)
	Tspike=10	(ms)
	Nspike=1

}

ASSIGNED { 
	iampa		(nA)  
	local_v	(mV):local voltage
}
STATE {
	gampa

}

INITIAL {
      gampa=0 

}    

BREAKPOINT {  
    
	LOCAL count
	SOLVE state METHOD cnexp
	FROM count=0 TO Nspike-1 {
		IF(at_time(count*Tspike+del)){
			state_discontinuity( gampa, gampa+ gmax)
		}
	}

	iampa= (1e-3)*gampa* (v- e)
	local_v=v
}

DERIVATIVE state {
	gampa'=-gampa/tau_ampa
}