High frequency oscillations in a hippocampal computational model (Stacey et al. 2009)

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Accession:135902
"... Using a physiological computer model of hippocampus, we investigate random synaptic activity (noise) as a potential initiator of HFOs (high-frequency oscillations). We explore parameters necessary to produce these oscillations and quantify the response using the tools of stochastic resonance (SR) and coherence resonance (CR). ... Our results show that, under normal coupling conditions, synaptic noise was able to produce gamma (30–100 Hz) frequency oscillations. Synaptic noise generated HFOs in the ripple range (100–200 Hz) when the network had parameters similar to pathological findings in epilepsy: increased gap junctions or recurrent synaptic connections, loss of inhibitory interneurons such as basket cells, and increased synaptic noise. ... We propose that increased synaptic noise and physiological coupling mechanisms are sufficient to generate gamma oscillations and that pathologic changes in noise and coupling similar to those in epilepsy can produce abnormal ripples."
Reference:
1 . Stacey WC, Lazarewicz MT, Litt B (2009) Synaptic noise and physiological coupling generate high-frequency oscillations in a hippocampal computational model. J Neurophysiol 102:2342-57 [PubMed]
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Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism: Hippocampus;
Cell Type(s): Hippocampus CA1 pyramidal GLU cell; Hippocampus CA3 pyramidal GLU cell; Hippocampus CA1 interneuron oriens alveus GABA cell; Hippocampus CA1 basket cell;
Channel(s): I Na,t; I A; I K; I h;
Gap Junctions: Gap junctions;
Receptor(s): GabaA; AMPA; NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Oscillations;
Implementer(s): Lazarewicz, Maciej [mlazarew at gmu.edu]; Stacey, William [wstacey at med.umich.edu];
Search NeuronDB for information about:  Hippocampus CA1 pyramidal GLU cell; Hippocampus CA3 pyramidal GLU cell; Hippocampus CA1 interneuron oriens alveus GABA cell; GabaA; AMPA; NMDA; I Na,t; I A; I K; I h;
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//
//  NOTICE OF COPYRIGHT AND OWNERSHIP OF SOFTWARE
//
// Copyright 2010, The University Of Michigan
// 	
//   All rights reserved.
//   For research use only; commercial use prohibited.
//   No Distribution without permission of William Stacey
//   wstacey@umich.edu
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



begintemplate IApp

public set, get, getloc, set_random, getConv, setValue, set_random_play

objref  iapp, iappR, loc, rR, rC, rD




// =================================================================================================
//
// init()
//
// ================================================================================================= 
proc init() {

    loc = new SectionRef()
	loc.sec iappR = new IClamp(0.5)
    loc.sec iapp  = new IClamp(0.5)
}




// =================================================================================================
//
// set()
//
// ================================================================================================= 
proc set() {
    //print "SET"
    if (numarg()==1 || numarg()==2) {
    
        iapp.dur = 1e9        
        iapp.del = 0

        if (numarg()==2) iapp.del = $2

        loc.sec iapp.amp = $1 * area(0.5) * 1e-5
    
    } else {
        
        print "USAGE: set( i (uA/cm2) )"
        
    }
}




// =================================================================================================
//
// getConv()
//
// ================================================================================================= 
func getConv() { local c

    loc.sec  c = area(0.5) * 1e-5 
    return c
}




// ========================================================================
//
// setValue( i [nA], { del [ms]} )
//
// ========================================================================
proc setValue() {
    //print "SETVALUE"
    if (numarg()==1 || numarg()==2) {
    
        iapp.dur = 1e9        
        iapp.del = 0

        if (numarg()==2) iapp.del = $2

        loc.sec iapp.amp = $1
    
    } else {
        
        print "USAGE: set( i (nA) )"
        
    }
}



// =================================================================================================
//
// set_random_play(mean, sd, isUnitsPerCm2, gid)
//
// ================================================================================================= 
proc set_random_play() {local mean, sd
   
   		mean          = $1
   		sd            = $2
   		isUnitsPerCm2 = $3
   		
   		//loc.sec print secname(), " mean=", mean, " sd=", sd, "UNITS:", isUnitsPerCm2
   		
   		if (isUnitsPerCm2) {
   		// conversion from uA/cm2 to nA
   			loc.sec mean = 1e-5 * mean * area(0.5)
 			loc.sec	sd   = 1e-5 * sd   * area(0.5)
 			
   			//loc.sec print secname(), " mena=", mean, " sd=", sd 
   		}else{
   		// otherwise mean and sd are in pA, and need to be converted to nA
   			mean = 1e-3 * mean
   			sd   = 1e-3 * sd
   			//loc.sec print secname(), " mean=", mean, " sd=", sd 
   		}
        
        rD       = new Random((startsw()+$4)%10000)
        
        iappR.del     = 0 //rD.uniform(0, 750) //###changed to 0 7/8/8
        iappR.dur     = 1e9
        
        //loc.sec print secname(), iappR.del
        
        rR = new Random((startsw()*$4)%10000)
        rR.normal(mean, sd*sd)
        rR.play(&iappR.amp)
}




// =================================================================================================
//
// set_random()
//
// ================================================================================================= 
proc set_random() {
   
        rC       = new Random((startsw()+$1)%10000)
        iapp.dur = rC.uniform(0, 500)      
        iapp.del = 0
        loc.sec iapp.amp = rC.uniform(-5, 5) * area(0.5) * 1e-5
        //print "amp: ", iappR.amp, secname(), $1
}




// =================================================================================================
//
// getloc()
//
// ================================================================================================= 
proc getloc() {
    
    loc.sec print secname() 
}




// =================================================================================================
//
// get()
//
// ================================================================================================= 
proc get() {
    loc.sec printf("iapp = %g (nA), loc= %s\n", iapp.amp, secname())
}

endtemplate IApp