AP back-prop. explains threshold variability and rapid rise (McCormick et al. 2007, Yu et al. 2008)

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Accession:135839
This simple axon-soma model explained how the rapid rising phase in the somatic spike is derived from the propagated axon initiated spike, and how the somatic spike threshold variance is affected by spike propagation.
References:
1 . McCormick DA, Shu Y, Yu Y (2007) Hodgkin and Huxley model still standing? Nature 445:E1-E2 [PubMed]
2 . Yu Y, Shu Y, McCormick DA (2008) Cortical action potential backpropagation explains spike threshold variability and rapid-onset kinetics. J Neurosci 28:7260-72 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Neuron or other electrically excitable cell; Axon;
Brain Region(s)/Organism: Neocortex;
Cell Type(s): Neocortex V1 pyramidal corticothalamic L6 cell; Neocortex V1 pyramidal intratelencephalic L2-6 cell;
Channel(s): I Na,t; I L high threshold; I T low threshold; I A; I K; I M; I h; I K,Ca; I_AHP;
Gap Junctions:
Receptor(s): GabaA; NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Action Potential Initiation; Detailed Neuronal Models;
Implementer(s):
Search NeuronDB for information about:  Neocortex V1 pyramidal corticothalamic L6 cell; Neocortex V1 pyramidal intratelencephalic L2-6 cell; GabaA; NMDA; I Na,t; I L high threshold; I T low threshold; I A; I K; I M; I h; I K,Ca; I_AHP;
/
McCormickEtAl2007YuEtAl2008
readme.txt
ca.mod *
cad.mod *
caL3d.mod *
capump.mod
gabaa5.mod *
Gfluct.mod *
ia.mod *
iahp.mod *
iahp2.mod *
ih.mod
im.mod *
kca.mod *
km.mod *
kv.mod *
na.mod *
NMDA_Mg.mod *
nmda5.mod *
release.mod *
for_plot_spike.m
mosinit.hoc
neuron_soma.dat
Rapid_rising_somatic_spike_soma_axon.hoc
                            
TITLE detailed model of glutamate NMDA receptors

COMMENT
-----------------------------------------------------------------------------

	Kinetic model of NMDA receptors
	===============================

	5-state gating model:
	Clements & Westbrook 1991. Neuron 7: 605.
	Lester & Jahr 1992. J Neurosci 12: 635.
	Edmonds & Colquhoun 1992. Proc. R. Soc. Lond. B 250: 279.
	Hessler, Shirke & Malinow. 1993. Nature 366: 569.
	Clements et al. 1992. Science 258: 1498.
  
	C -- C1 -- C2 -- O
	           |
      	           D

	Voltage dependence of Mg2+ block:
	Jahr & Stevens 1990. J Neurosci 10: 1830.
	Jahr & Stevens 1990. J Neurosci 10: 3178.

-----------------------------------------------------------------------------

  Based on voltage-clamp recordings of NMDA receptor-mediated currents in rat
  hippocampal slices (Hessler et al., Nature 366: 569-572, 1993), this model 
  was fit directly to experimental recordings in order to obtain the optimal
  values for the parameters (see Destexhe, Mainen and Sejnowski, 1996).

-----------------------------------------------------------------------------

  This mod file does not include mechanisms for the release and time course
  of transmitter; it is to be used in conjunction with a sepearate mechanism
  to describe the release of transmitter and that provides the concentration
  of transmitter in the synaptic cleft (to be connected to pointer C here).

-----------------------------------------------------------------------------

  See details in:

  Destexhe, A., Mainen, Z.F. and Sejnowski, T.J.  Kinetic models of 
  synaptic transmission.  In: Methods in Neuronal Modeling (2nd edition; 
  edited by Koch, C. and Segev, I.), MIT press, Cambridge, 1998, pp 1-25.

  (electronic copy available at http://cns.iaf.cnrs-gif.fr)


  Written by Alain Destexhe and Zach Mainen, 1995

-----------------------------------------------------------------------------
ENDCOMMENT

INDEPENDENT {t FROM 0 TO 1 WITH 1 (ms)}

NEURON {
	POINT_PROCESS NMDA5
	POINTER C
	RANGE C0, C1, C2, D, O, B
	RANGE g, gmax, rb
	GLOBAL Erev, mg, Rb, Ru, Rd, Rr, Ro, Rc
	GLOBAL vmin, vmax
	NONSPECIFIC_CURRENT i
}

UNITS {
	(nA) = (nanoamp)
	(mV) = (millivolt)
	(pS) = (picosiemens)
	(umho) = (micromho)
	(mM) = (milli/liter)
	(uM) = (micro/liter)
}

PARAMETER {

	Erev	= 0    (mV)	: reversal potential
	gmax	= 500  (pS)	: maximal conductance
	mg	= 0    (mM)	: external magnesium concentration
	vmin = -120	(mV)
	vmax = 100	(mV)
	
: Rates

	: Destexhe, Mainen & Sejnowski, 1996
	Rb	= 5e-3    (/uM /ms)	: binding 		
	Ru	= 12.9e-3  (/ms)	: unbinding		
	Rd	= 8.4e-3   (/ms)	: desensitization
	Rr	= 6.8e-3   (/ms)	: resensitization 
	Ro	= 46.5e-3   (/ms)	: opening
	Rc	= 73.8e-3   (/ms)	: closing
}

COMMENT
	: Clements et al. 1992
	Rb	= 5e-3    (/uM /ms)	: binding 		
	Ru	= 9.5e-3  (/ms)	: unbinding		
	Rd	= 16e-3   (/ms)	: desensitization
	Rr	= 13e-3   (/ms)	: resensitization 
	Ro	= 25e-3   (/ms)	: opening
	Rc	= 59e-3   (/ms)	: closing

	: Hessler Shirke & Malinow 1993
	Rb	= 5e-3    (/uM /ms)	: binding 		
	Ru	= 9.5e-3  (/ms)	: unbinding		
	Rd	= 16e-3   (/ms)	: desensitization
	Rr	= 13e-3   (/ms)	: resensitization 
	Ro	= 25e-3   (/ms)	: opening
	Rc	= 59e-3   (/ms)	: closing

	: Clements & Westbrook 1991
	Rb	=  5    (uM /s)	: binding 		
	Ru	=  5	(/s)	: unbinding -> gives Kd = Rb/Ru = 1 uM
	Rd	=  4.0  (/s)	: desensitization
	Rr	=  0.3  (/s)	: resensitization 
	Ro	= 10  (/s)	: opening
	Rc	= 322   (/s)	: closing

	: Edmonds & Colquhoun 1992
	Rb	=  5    (uM /s)	: binding 		
	Ru	=  4.7  (/s)	: unbinding		
	Rd	=  8.4  (/s)	: desensitization
	Rr	=  1.8  (/s)	: resensitization 
	Ro	= 46.5  (/s)	: opening
	Rc	= 91.6  (/s)	: closing

	: Lester & Jahr 1992
	Rb	= 5    (uM /s)	: binding 		
	Ru	= 6.7   (/s)	: unbinding		
	Rd	= 15.2  (/s)	: desensitization
	Rr	= 9.4   (/s)	: resensitization 
	Ro	= 83.8  (/s)	: opening
	Rc	= 83.8  (/s)	: closing

ENDCOMMENT


ASSIGNED {
	v		(mV)		: postsynaptic voltage
	i 		(nA)		: current = g*(v - Erev)
	g 		(pS)		: conductance
	C 		(mM)		: pointer to glutamate concentration

	rb		(/ms)    : binding
}

STATE {
	: Channel states (all fractions)
	C0		: unbound
	C1		: single bound
	C2		: double bound
	D		: desensitized
	O		: open

	B		: fraction free of Mg2+ block
}

INITIAL {
	rates(v)
	C0 = 1
}

BREAKPOINT {
	rates(v)
	SOLVE kstates METHOD sparse

	g = gmax * O * B
	i = (1e-6) * g * (v - Erev)
}

KINETIC kstates {
	
	rb = Rb * (1e3) * C 

	~ C0 <-> C1	(rb,Ru)
	~ C1 <-> C2	(rb,Ru)
	~ C2 <-> D	(Rd,Rr)
	~ C2 <-> O	(Ro,Rc)

	CONSERVE C0+C1+C2+D+O = 1
}

PROCEDURE rates(v(mV)) {
	TABLE B
	DEPEND mg
	FROM vmin TO vmax WITH 200

	: from Jahr & Stevens

	B = 1 / (1 + exp(0.062 (/mV) * -v) * (mg / 3.57 (mM)))
}


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