Balance of excitation and inhibition (Carvalho and Buonomano 2009)

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Accession:125689
" ... Here, theoretical analyses reveal that excitatory synaptic strength controls the threshold of the neuronal input-output function, while inhibitory plasticity alters the threshold and gain. Experimentally, changes in the balance of excitation and inhibition in CA1 pyramidal neurons also altered their input-output function as predicted by the model. These results support the existence of two functional modes of plasticity that can be used to optimize information processing: threshold and gain plasticity."
Reference:
1 . Carvalho TP, Buonomano DV (2009) Differential effects of excitatory and inhibitory plasticity on synaptically driven neuronal input-output functions. Neuron 61:774-85 [PubMed]
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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):
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON; MATLAB;
Model Concept(s): Synaptic Integration;
Implementer(s):
objectvar g[10]                 // max 10 graphs
ngraph = 0
proc addgraph() { local ii      // define subroutine to add a new graph
        ngraph = ngraph+1
        ii = ngraph-1
        g[ii] = new Graph(0)	// With 0 argument will NOT map window to screen (but .view will!)
        g[ii].size(0,tstop,$2,$3) // $2 = ystart coordinates; $3 = yend coordinates
	g[ii].view(0,$2,tstop,$3, $4,$5,$6,$7)
        g[ii].xaxis(0)
        g[ii].yaxis()
        g[ii].addvar($s1,1,1)
        g[ii].family(0)         // 0/1=nooverlay/overlay lines
        g[ii].save_name("graphList[0].")
        graphList[0].append(g[ii])
}

proc addline() {
        g[$1].addexpr($s2,$3,1)
}

////////////////////////////////////////////////////////////////////////////////////
////////////////////   TRIAL PLOTS  //////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////

objectvar   plottrial
proc initPlotTrial() {
        plottrial = new Graph()
        plottrial.size(0,$1,-2,10)
        plottrial.xaxis()
        plottrial.yaxis()
        plottrial.beginline(0,0)
}
proc PlotTrial() {
        plottrial.mark($1,$2,$s3,$4,$5,1)
        plottrial.flush()
}


////////////////////////////////////////////////////////////////////////////////////
////////////////////   CONNECTIVITY   //////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////

objectvar       plotconnecEx
connecEECount = 0                                                       //counts # of times connecEE was called
connecEEminW  = 0
connecEEmaxW  = AmpaMaxExEx
double baseweights[nEx][nEx_Ex]

ncolor=9
objref sq[ncolor], SQ[ncolor], tri[ncolor], TRI[ncolor], oh[ncolor], OH[ncolor]
proc mkgl() {local x
	x = .025
	$o1 = new Glyph()
	if ($4 == 0) { // square
		$o1.path.m(-x, -x).l(-x, x).l(x, x).l(x,-x).close
	}else if ($4 == 1) { // triangle
		$o1.path.m(-x, -x).l(0,x).l(x,-x).close
	}else if ($4 == 2) { // circle (not a very fast shape)
				// might be better off using a gif
		ellipse_path($o1, x, x)
	}
	if ($3 == 0) {
		$o1.s($2,1)
	}else{
		$o1.fill($2)
	}
}
proc ellipse_path() {local p0, p1, p2, p3, p4, px0, px1, px2, px3, px4, rx, ry, x, y
	x = 0  y = 0
	rx = $2  ry = $3
	// following from iv/src/lib/IV-Mac/canvas.cpp
	p0 = 1.00000000
	p1 = 0.89657547   // cos 30 * sqrt(1 + tan 15 * tan 15)
	p2 = 0.70710678   // cos 45
	p3 = 0.51763809   // cos 60 * sqrt(1 + tan 15 * tan 15)
	p4 = 0.26794919   // tan 15
	px0 = p0 * rx  py0 = p0 * ry
	px1 = p1 * rx  py1 = p1 * ry
	px2 = p2 * rx  py2 = p2 * ry
	px3 = p3 * rx  py3 = p3 * ry
	px4 = p4 * rx  py4 = p4 * ry

	$o1.path()
	$o1.m(x + rx, y)
	$o1.curve(px2, y + py2, x + px0, y + py4, x + px1, y + py3)
	$o1.curve(x, y + ry, x + px3, y + py1, x + px4, y + py0)
	$o1.curve(x - px2, y + py2, x - px4, y + py0, x - px3, y + py1)
	$o1.curve(x - rx, y, x - px1, y + py3, x - px0, y + py4)
	$o1.curve(x - px2, y - py2, x - px0, y - py4, x - px1, y - py3)
	$o1.curve(x, y - ry, x - px3, y - py1, x - px4, y - py0)
	$o1.curve(x + px2, y - py2, x + px4, y - py0, x + px3, y - py1)
	$o1.curve(x + rx, y, x + px1, y - py3, x + px0, y - py4)
	$o1.close
}

for i=1,ncolor-1 {
	mkgl(sq[i],i,0,0)  mkgl(SQ[i], i, 1,0)
	mkgl(tri[i],i,0,1)  mkgl(TRI[i], i, 1,1)
	mkgl(oh[i],i,0,2)  mkgl(OH[i], i, 1,2)
}

proc connecEx() {local numpost, numpre, numpresyn, x, y, sizemax, size, color, tt
        sizemax = 10
        //numpost = nEx
        //numpre  = nEx
        
	numpost = 1
	numpre = 1

	numpresyn = nEx_Ex
        // IF FIRST CALL OPEN GRAPH AND GET INITIAL Ws
        if (connecEECount==0) {
                plotconnecEx = new Graph(1)
                plotconnecEx.size(0,numpost,-2,numpre)
		//plotconnecEx.view(0,numpost,-2,numpre, 100,0,100,100)
                //for (x=0;x<numpost;x=x+1) {
                  x = 1
		  for (y=0;y<numpresyn;y=y+1) {
                      baseweights[x][y]=sExEx[x][y].gmaxAMPA
                  }
                //}
        }                                                                               // end of connecEECount=0

        plotconnecEx.erase_all()
        //for (x=0;x<numpost;x=x+1) {
        x = 1
	   
	   //connecEEselec[x][stim-1] = Ex[x].soma.Ca_CaSOMA
           for (y=0;y<numpresyn;y=y+1) {
                ypoint = sExEx[x][y].precell
                size = (sExEx[x][y].gmaxAMPA-connecEEminW)/(connecEEmaxW-connecEEminW)*sizemax+1
                if (sExEx[x][y].gmaxAMPA>=connecEEmaxW) { color = 2
                } else { color = 3 }
                plotconnecEx.glyph(sq[color], x+y*0.01,ypoint, size, size, 0)
                size = (baseweights[x][y]-connecEEminW)/(connecEEmaxW-connecEEminW)*sizemax+1
                plotconnecEx.glyph(SQ[3], x+y*0.01,ypoint, size, size, 0)
           }
        // plotconnecEx.beginline(1,2)
        // plotconnecEx.line(x+0.1,0)
        // plotconnecEx.line(x+0.1,Ex1[x].soma.Ca_CaSOMA)
        //}


        connecEECount=1
        plotconnecEx.label(0.5,0.95,"Triang=Inh->Ex")
        plotconnecEx.label(0.5,0.9,"Circ=Ex->Inh")

        plotconnecEx.crosshair_action("ExConnections")


}                                                                                               // END proc connecEE()

///////////////// Ex->Inh Weights
connecExInhCount = 0                                                      //counts # of times connecEE was called
connecExInhminW  = 0
connecExInhmaxW  = AmpaMaxExInh
double baseweightsExInh[nInh][nEx_Inh]
//double connecEEselec[nEx][numStim]
proc connecExInh() {local numpost, numpre, numpresyn, x, y, sizemax, size, color
        sizemax = 10
        numpost = nInh
        numpre  = nEx
        numpresyn = nEx_Inh
        // IF FIRST CALL OPEN GRAPH AND GET INITIAL Ws
        if (connecExInhCount==0) {
                for (x=0;x<numpost;x=x+1) {
                        for (y=0;y<numpresyn;y=y+1) {
                                baseweightsExInh[x][y]=sExInh[x][y].gmaxAMPA
                        }
                }
        }                                                                               // end of connecEECount=0

        for (x=0;x<numpost;x=x+1) {
           //connecEEselec[x][stim-1] = Ex[x].soma.Ca_CaSOMA
           for (y=0;y<numpresyn;y=y+1) {
                        ypoint = sExInh[x][y].precell
                        size = (baseweightsExInh[x][y]-connecExInhminW)/(connecExInhmaxW-connecExInhminW)*sizemax+1
                        plotconnecEx.glyph(OH[4], x+y*0.01+0.2,ypoint,size, size,0)
                        size = (sExInh[x][y].gmaxAMPA-connecExInhminW)/(connecExInhmaxW-connecExInhminW)*sizemax+1
                        if (sExInh[x][y].gmaxAMPA>=connecExInhmaxW) { color = 2
                        } else { color = 4 }
                        plotconnecEx.glyph(oh[color], x+y*0.01+0.2,ypoint,size,size,0)
           }
        // plotconnecEx.beginline(1,2)
        // plotconnecEx.line(x+0.1,0)
        // plotconnecEx.line(x+0.1,Ex1[x].soma.Ca_CaSOMA)
        }


        connecExInhCount=1

}                                                                                               // END proc connecEE()


///////////////// Inh->Ex Weights
connecInhExCount = 0                                                      //counts # of times connecEE was called
connecInhExminW  = 0.002
connecInhExmaxW  = GabaMax
double baseweightsInhEx[nEx][nInh_Ex]
proc connecInhEx() {local numpost, numpre, numpresyn, x, y, sizemax, size, color
        sizemax = 10
        numpost = nEx
        numpre  = nInh
        numpresyn = nInh_Ex
        // IF FIRST CALL OPEN GRAPH AND GET INITIAL Ws
        if (connecInhExCount==0) {
                x = 1
		//for (x=0;x<numpost;x=x+1) {
                        for (y=0;y<numpresyn;y=y+1) {
                                baseweightsInhEx[x][y]=sInhEx[x][y].gmaxGABA
                        }
                //}
        }                                                                               // end of connecEECount=0

        //for (x=0;x<numpost;x=x+1) {
	x = 1
           //connecEEselec[x][stim-1] = Ex[x].soma.Ca_CaSOMA
           for (y=0;y<numpresyn;y=y+1) {
                        ypoint = sInhEx[x][y].precell
                        size = (baseweightsInhEx[x][y]-connecInhExminW)/(connecInhExmaxW-connecInhExminW)*sizemax+1
                        plotconnecEx.glyph(TRI[6], x+y*0.01,ypoint+0.2,size,size,0)
                        size = (sInhEx[x][y].gmaxGABA-connecInhExminW)/(connecInhExmaxW-connecInhExminW)*sizemax+1
                        if (sInhEx[x][y].gmaxGABA>=connecInhExmaxW) { color = 2
                        } else { color = 7 }
                        plotconnecEx.glyph(tri[color],x+y*0.01,ypoint+0.2,size,size,0)
           }
        // plotconnecEx.beginline(1,2)
        // plotconnecEx.line(x+0.1,0)
        // plotconnecEx.line(x+0.1,Ex1[x].soma.Ca_CaSOMA)
        //}


        connecInhExCount=1

}                                                                                               // END proc connecEE()


////////////////////////////////////////////////////////////////////////////////////
////////////////////   INTERACTIVE CONNECTIVITY   //////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////

proc ExConnections() {local numpost, numpre, post, pre, numpresyn, x, y, sizemax, size, color

    post = int($1)
        plotconnecEx.beginline(2,2)
        plotconnecEx.line(post,0)
        plotconnecEx.line(post,-1)

   numpresyn = nEx_Ex
   for (y=0;y<numpresyn;y=y+1) {
                ypoint = sExEx[post][y].precell
        plotconnecEx.mark(0,ypoint,"S",8,5,1)
        print "Post=",post,"Pre=",ypoint,"W=",sExEx[post][y].gmaxAMPA,"D=",sExEx[post][y].Delay
   }
   yscale = nEx/nInh
   numpresyn = nInh_Ex
   for (y=0;y<numpresyn;y=y+1) {
                ypoint = sInhEx[post][y].precell
        plotconnecEx.mark(post,ypoint*yscale,"T",6,4,1)
   }

}

proc PrintConnections() {

   post = int($1)
   strdef dummystr
   numpresyn = nEx_Ex
   for (y=0;y<numpresyn;y=y+1) {
        sprint(dummystr,"Post=%4d, ExPre(%3d)=%4d, W=%10.8f, D=%4.2f",post,y,sExEx[post][y].precell,sExEx[post][y].gmaxAMPA,sExEx[post][y].Delay)
        print dummystr
   }
   
}