Membrane potential changes in dendritic spines during APs and synaptic input (Palmer & Stuart 2009)

 Download zip file   Auto-launch 
Help downloading and running models
Accession:120798
" ... Finally, we used simulations of our experimental observations in morphologically realistic models to estimate spine neck resistance. These simulations indicated that spine neck resistance ranges up to ~500 M Ohm. Spine neck resistances of this magnitude reduce somatic EPSPs by ~15%, indicating that the spine neck is unlikely to act as a physical device to significantly modify synaptic strength."
Reference:
1 . Palmer LM, Stuart GJ (2009) Membrane potential changes in dendritic spines during action potentials and synaptic input. J Neurosci 29:6897-903 [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):
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Active Dendrites; Influence of Dendritic Geometry; Synaptic Integration;
Implementer(s): Morse, Tom [Tom.Morse at Yale.edu]; Stuart, Greg J. [greg.stuart at anu.edu.au];
// --------------------------------------------------------------
//  Initialise user-defined membrane parameters 
// --------------------------------------------------------------

celsius=37		// nominal temperature of simulation
Ri=105    		// internal resistivity in ohm-cm 
Cm=1      		// specific membrane capacitance in uF/cm^2
Rm=17000      	// specific membrane resistivity in ohm/cm^2 
v_init=-75	     	// resting membrane potential
spinescale=2.0 	// factor used to membrane area to account for spines


// --------------------------------------------------------------------
// Add spines to dend1[881], dend1[876] and dend1[905]
// (79, 40 um and 140 um from the soma, respectively)
// --------------------------------------------------------------------	


access dend1[876]    /* dendritic segment with spine */
nseg=20

access dend1[881]    /* dendritic segment with spine */
nseg=20

access dend1[905]    /* dendritic segment with spine */
nseg=20


create spine_head[3], spine_neck[3]

dend1[881] connect spine_neck[0](0), 0.5
spine_neck connect spine_head[0](0), 1
spine_neck[0] {nseg=1 L=1 diam=0.051}		// spine neck resistance ~500 MOhm
spine_head[0] {nseg=1 L=1 diam=1}

dend1[876] connect spine_neck[1](0), 0.5
spine_neck[1] connect spine_head[1](0), 1
spine_neck[1] {nseg=1 L=1 diam=0.1156}		// spine neck resistance ~100 MOhm 
spine_head[1] {nseg=1 L=1 diam=1}

dend1[905] connect spine_neck[2](0), 0.5
spine_neck[2] connect spine_head[2](0), 1
spine_neck[2] {nseg=1 L=1 diam=0.1156}		// spine neck resistance ~100 MOhm 
spine_head[2] {nseg=1 L=1 diam=1}




// ----------------------------------------------------------------------------
// initialize passive properties and add virtual spines by scaling Rm and Cm
//-----------------------------------------------------------------------------


forall {insert pas g_pas=1/(Rm/spinescale) cm=Cm*spinescale Ra=Ri e_pas=v_init}


// -----------------------------------------------------------------------
// 	correction for spineless areas: soma, 1st 100 um of apical dendrite,
// 	and 1st 20 um of each basal dendrite
//------------------------------------------------------------------------
	 

	for i=20,24 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
	 for i=35,39 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
	 for i=63,64 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
	 for i=769,770 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
 	for i=800,802 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
	 for i=915,916 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
	 for i=949,951 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
	 for i=998,999 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
	 for i=1047,1050 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
	 for i=1051,1052 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }
	 for i=1059,1061 {
		dend1[i]  {g_pas=1/Rm cm = Cm}
	 }



// -----------------------------------------------------------------------
// 	correction for spine properties 
//------------------------------------------------------------------------


	for i=0,2 {
		spine_head[i] {g_pas=1/Rm cm = Cm}
		spine_neck[i] {g_pas=1/Rm cm = Cm}

	}


Loading data, please wait...