Contrast invariance by LGN synaptic depression (Banitt et al. 2007)

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Accession:114637
"Simple cells in layer 4 of the primary visual cortex of the cat show contrast-invariant orientation tuning, in which the amplitude of the peak response is proportional to the stimulus contrast but the width of the tuning curve hardly changes with contrast. This study uses a detailed model of spiny stellate cells (SSCs) from cat area 17 to explain this property. The model integrates our experimental data, including morphological and intrinsic membrane properties and the number and spatial distribution of four major synaptic input sources of the SSC: the dorsal lateral geniculate nucleus (dLGN) and three cortical sources. ... The model response is in close agreement with experimental results, in terms of both output spikes and membrane voltage (amplitude and fluctuations), with reasonable exceptions given that recurrent connections were not incorporated."
Reference:
1 . Banitt Y, Martin KA, Segev I (2007) A biologically realistic model of contrast invariant orientation tuning by thalamocortical synaptic depression. J Neurosci 27:10230-9 [PubMed]
2 . Anderson JC, Douglas RJ, Martin KA, Nelson JC (1994) Map of the synapses formed with the dendrites of spiny stellate neurons of cat visual cortex. J Comp Neurol 341:25-38 [PubMed]
3 . Anderson JC, Douglas RJ, Martin KA, Nelson JC (1994) Synaptic output of physiologically identified spiny stellate neurons in cat visual cortex. J Comp Neurol 341:16-24 [PubMed]
4 . Banitt Y, Martin KA, Segev I (2005) Depressed responses of facilitatory synapses. J Neurophysiol 94:865-70 [PubMed]
Citations  Citation Browser
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): Neocortex spiny stellate cell;
Channel(s): I Na,t; I A; I K; I K,Ca; I Calcium;
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Pattern Recognition; Activity Patterns; Parameter Fitting; Active Dendrites; Synaptic Integration; Vision;
Implementer(s):
Search NeuronDB for information about:  I Na,t; I A; I K; I K,Ca; I Calcium;
/
SSC_model
ReadMe.html
ReadMe_orig
iA.mod
iap.mod
ic.mod
ical.mod
VectorSynNS.mod
axon.hoc
InitArrays.hoc
InitSSCArrays.hoc
InitSynapses.hoc
j3886d_sdt.hoc
MeasureDist.hoc
mosinit.hoc
ssc.hoc
sscDistCl1
sscDistCl2
sscDistCl3
sscDistCl4
sscProxCl1
sscProxCl2
sscProxCl3
sscProxCl4
sscSomaCl1 *
sscSomaCl2 *
sscSomaCl3 *
sscSomaCl4 *
                            
//detailed Spiny Stellate cell model from cat V1L4

xopen("j3886d_sdt.hoc")
xopen("axon.hoc")
create_axon()

/******************
dividing dendritic tree to proximal and distal parts as in Anderson et al. 1994 (under and over 50 um from soma, respectively). soma.L=10, hence ProxDef=60. the following hoc file has functions  that measure the length and other morphological details of the proximal and distal parts of the tree. total length of sscell before incorporation of spine area is 5570 um. (Proximal length is 524 um)
*********************/
ProxDef=60
xopen("MeasureDist.hoc")

/********************
inserting passive properties:
********************/
forall {
	Ra=200
	insert pas
	g_pas=1/12000
	e_pas=-65
	cm=1
	nseg=1			//for a more accurate computation use: nseg=int(L/20)+1}
}

/**********************
voltage dependent conductances in soma and axon (dendrites are passive):
*********************/
soma{
  insert iapnew
  gnabar_iapnew=0.15	//equivalent to 1500 pS/um^2
  gkbar_iapnew=0.07
  insert iA
  gkbar_iA=0.01
  actvha_iA=50
  inactvha_iA=60
  insert icalnew
  gcabar_icalnew=0.0045
  insert icnew
  gkbar_icnew=0.0095
}

hill{
  insert iapnew
  gnabar_iapnew=0.1	
  gkbar_iapnew=0.07
  insert iA
  gkbar_iA=0.01
  actvha_iA=50
  inactvha_iA=60
  insert icalnew
  gcabar_icalnew=0.0045
  insert icnew
  gkbar_icnew=0.0095
}

iseg{
  insert iapnew
  gnabar_iapnew=0.1	
  gkbar_iapnew=0.07
  insert iA
  gkbar_iA=0.01
  actvha_iA=50
  inactvha_iA=60
  insert icalnew
  gcabar_icalnew=0.0045
  insert icnew
  gkbar_icnew=0.0095
}
naactvha_iapnew=28
kactvha_iapnew=28
naiactvha_iapnew=33
caactvha_icalnew=-10

/*************************************
following files define the number and distribution of synapses on the dendritic tree
************************************/
//Lists with # of synapses, specific to ssc:
xopen("InitSSCArrays.hoc")	

//Define lists of synapses, netstims and netcons (based on "InitSSCArrays.hoc").
xopen("InitArrays.hoc")

//Define methods to let user initialize the synapses and netstims:
xopen ("InitSynapses.hoc")

//adjusting dendrites to include spines area. performed here since
//all previous calculation have to be performed 
//before changing lengths of dendritic tree:
adjust_for_spines()


/***************************************
simulation for example:
***************************************/
/*newPlotV(0.5)
for j=1,4{							//four input sources
	for i=0,2{						//soma, proximal, distal
		//WriteSynLoc(j,i)
		ReadSynapses(j,i)
		SetInputSourceLocationFrequency(j,i,0,40,1)
	}
}
nrncontrolmenu()
v_init=-65
access soma
distance()
tstop=200
init()
run()