CA1 pyramidal neuron: Synaptic Scaling (Magee, Cook 2000)

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Accession:7509
Jeffrey Magee and Erik Cook found evidence in experiments and modeling that support the hypothesis that an increase in synaptic conductance for synapses at larger distances from the soma is responsible for reducing the location dependence (relative to the soma) of synapses.
Reference:
1 . Magee JC, Cook EP (2000) Somatic EPSP amplitude is independent of synapse location in hippocampal pyramidal neurons. Nat Neurosci 3:895-903 [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:
Cell Type(s): Hippocampus CA1 pyramidal GLU cell;
Channel(s):
Gap Junctions:
Receptor(s): AMPA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Influence of Dendritic Geometry;
Implementer(s): Magee, Jeffrey [jmagee at lsumc.edu];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal GLU cell; AMPA;
/
magee2000
readme.txt
ca1.nrn
main.hoc
main_example_epsps.hoc
mosinit.hoc
shape_plot.ses
                            
// main_example_epsps.hoc
	strdef label_str
	
	//load_file("nrngui.hoc")
	
	print "--------------"

	// open CA1 neuron model and set passive params
	xopen("ca1.nrn")	
	
	for i = 0, nDend-1 {
		d[i] {
			cm = 1
			insert pas
			g_pas = 1/10000
			e_pas = -65
			v = -65
			finitialize(v)
		}
	}
	
	s {
		cm = 1
		insert pas
		g_pas = 1/10000
		e_pas = -65
		v = -65
		finitialize(v)
	}
	
	forall Ra = 70
	
	vRest = -65
	tStop = 40
	dt = .05
	
	s distance()
	
	// synapse object
	objref s1
	
	num_of_synapses = 3
		// set up plotting
		objref g2[num_of_synapses]
		
	// below counter (cntr) moves synapse to different positions
	// with different conductances
	
	for synapse_pos_cntr = 0,num_of_synapses-1 {
	
	if (synapse_pos_cntr == 0 ) {

	//wopen("d38.out")
	i = 38
	gsyn = 1000e-6	
	label_str="Proximal"
	
	} else if (synapse_pos_cntr ==1) {
	
	//wopen("d153.out")
	i = 153
//	gsyn = 1900e-6
	gsyn = 1000e-6
	label_str="Distal"
	
	} else if (synapse_pos_cntr ==2) {
	
	// open output file
//	wopen("d268.out")
	
	// i is dendritic compartment for synapse
//	i = 268
	i = 153
// 	gsyn = 3000e-6
 	gsyn = 2000e-6
	label_str="Distal X2"
	
	}

	g2[synapse_pos_cntr] = new Graph()
	g2[synapse_pos_cntr].size(0, 20, -65,-64)
	g2[synapse_pos_cntr].addvar("s.v(.5)",1,1)
	g2[synapse_pos_cntr].exec_menu("Keep Lines")
		
	g2[synapse_pos_cntr].addvar("d[i].v(.5)",2,1)
	d[i] {
		
				// place synapse on dendrite compartment d[i]
				s1 = new AlphaSynapse(.5)
				s1.gmax = gsyn
				s1.onset = 0
				s1.tau = 1
	
				// initialize simulation
				t = 0
				vp = vRest
				forall {
					v = vRest
					finitialize(vRest)
				}
				// g2.erase()
				g2[synapse_pos_cntr].begin()

				// run simulation
				while(t < tStop) {
					fadvance()
					g2[synapse_pos_cntr].plot(t)
					// fprint("%g %g %g\n",t,s.v(.5),d[i].v(.5))
				}
				
				g2[synapse_pos_cntr].flush()
				doNotify()

	}
	g2[synapse_pos_cntr].label(label_str)
//	g2[synapse_pos_cntr].exec_menu("View = plot")
//	g2[synapse_pos_cntr].size(0, 40, -65.5, -54)
	g2[synapse_pos_cntr].size(0, 40, -65, -64)
}
//	wopen()

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