Explaining pathological changes in axonal excitability by dynamical analysis (Coggan et al. 2011)

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Accession:143072
"... To help decipher the biophysical basis for ‘paroxysmal’ spiking, we replicated afterdischarge (i.e. continued spiking after a brief stimulus) in a minimal conductance-based axon model. ... A perturbation could abruptly switch the system between two (quasi-)stable attractor states: rest and repetitive spiking. ... Initiation of afterdischarge was explained by activation of the persistent inward current forcing the system to cross a saddle point that separates the basins of attraction associated with each attractor. Termination of afterdischarge was explained by the attractor associated with repetitive spiking being destroyed. ... The model also explains other features of paroxysmal symptoms, including temporal summation and refractoriness."
Reference:
1 . Coggan JS, Ocker GK, Sejnowski TJ, Prescott SA (2011) Explaining pathological changes in axonal excitability through dynamical analysis of conductance-based models. J Neural Eng 8:065002 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Axon;
Brain Region(s)/Organism:
Cell Type(s):
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: XPP;
Model Concept(s): Nociception;
Implementer(s): Prescott, Steven [steve.prescott at sickkids.ca]];
// multiple spikes

// see prev mdbeta_s.hocs for alt codes

load_file("nrngui.hoc")



load_file("sbeta_jcns.hoc")

///////////////////////////////////////////////////////


createAxon()

proc setupPhysiology() {
	setRacm()
	addchannels()
}



bursts = 1

spikesperburst = 6


//totalspikes = bursts*spikesperburst

totalspikes = 20

objref stim[totalspikes]

spikeinterval= 9

stimcounter = 1

tdelay = 25

burstinterval = 100

proc setupStim() {

for x = 1, bursts {
	for y = 1, spikesperburst {
	 
	soma {

		stim[stimcounter] = new IClamp(0.5)
		stim[stimcounter].del = (x-1)*burstinterval + (y-1)*spikeinterval + tdelay
		stim[stimcounter].amp = 1
		stim[stimcounter].dur = 0.8
                tstop = 300
		stimcounter = stimcounter +1


			}
		}
	}
 }





////////////////////////////////////////////////////////

setupPhysiology()
setupStim()

////////////////////////////////////////////////////////

access soma

init()


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