Linear vs non-linear integration in CA1 oblique dendrites (Gómez González et al. 2011)

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Accession:144450
The hippocampus in well known for its role in learning and memory processes. The CA1 region is the output of the hippocampal formation and pyramidal neurons in this region are the elementary units responsible for the processing and transfer of information to the cortex. Using this detailed single neuron model, it is investigated the conditions under which individual CA1 pyramidal neurons process incoming information in a complex (non-linear) as opposed to a passive (linear) manner. This detailed compartmental model of a CA1 pyramidal neuron is based on one described previously (Poirazi, 2003). The model was adapted to five different reconstructed morphologies for this study, and slightly modified to fit the experimental data of (Losonczy, 2006), and to incorporate evidence in pyramidal neurons for the non-saturation of NMDA receptor-mediated conductances by single glutamate pulses. We first replicate the main findings of (Losonczy, 2006), including the very brief window for nonlinear integration using single-pulse stimuli. We then show that double-pulse stimuli increase a CA1 pyramidal neuron’s tolerance for input asynchrony by at last an order of magnitude. Therefore, it is shown using this model, that the time window for nonlinear integration is extended by more than an order of magnitude when inputs are short bursts as opposed to single spikes.
Reference:
1 . Gómez González JF, Mel BW, Poirazi P (2011) Distinguishing Linear vs. Non-Linear Integration in CA1 Radial Oblique Dendrites: It's about Time. Front Comput Neurosci 5:44 [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): Hippocampus CA1 pyramidal GLU cell;
Channel(s): I Na,p; I CAN; I Sodium; I Calcium; I Potassium; I_AHP;
Gap Junctions:
Receptor(s): NMDA;
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Active Dendrites; Detailed Neuronal Models; Synaptic Integration;
Implementer(s):
Search NeuronDB for information about:  Hippocampus CA1 pyramidal GLU cell; NMDA; I Na,p; I CAN; I Sodium; I Calcium; I Potassium; I_AHP;
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CA1_Gomez_2011
mechanism
x86_64
ampa.mod *
cad.mod
cal.mod
calH.mod
can.mod *
car.mod
cat.mod
d3.mod *
gabaa.mod *
gabab.mod
h.mod
hha_old.mod
hha2.mod
ican.mod
ipulse1.mod *
ipulse2.mod *
kadist.mod
kaprox.mod
kca.mod
kct.mod
KdBG.mod
km.mod
nap.mod *
netstim.mod *
netstimmm.mod *
nmda.mod *
NMDAb.mod
somacar.mod
                            
TITLE t-type calcium channel with high threshold for activation
: used in somatic and dendritic regions 
:
: 
: Updated to use CVode --Carl Gold 08/10/03


NEURON {
	SUFFIX cat
	USEION ca READ cai, eca    
        USEION Ca WRITE iCa VALENCE 2
        : The T-current does not activate calcium-dependent K-currents
        RANGE gcatbar, iCa
        RANGE gcatbar, ica
	GLOBAL hinf, minf
}

UNITS {
	(mA) = (milliamp)
	(mV) = (millivolt)
	(molar) = (1/liter)
	(mM) =	(millimolar)
	FARADAY = (faraday) (coulomb)
	R = (k-mole) (joule/degC)
}

PARAMETER {           :parameters that can be entered when function is called in cell-setup 
:	gcatbar = 0.1e-7   (cm/s)  : initialized conductance
	gcatbar = 0   (mho/cm2)  : initialized conductance
	zetam = -3
	zetah = 5.2
	vhalfm =-36 (mV)
	vhalfh =-68 (mV)
	tm0=1.5(ms)
	th0=10(ms)
}



ASSIGNED {     : parameters needed to solve DE
	v            (mV)
	celsius      (degC)
	iCa          (mA/cm2)
:	ica          (mA/cm2)
	cai          (mM)       :5e-5 initial internal Ca++ concentration
	eca          (mV)       : initial external Ca++ concentration
        minf
        hinf
}


STATE {	
	m 
	h 
}  

INITIAL {
	rates(v)
        m = minf
        h = hinf
}

BREAKPOINT {
	SOLVE states METHOD cnexp

:	ecat = (1e3) * (R*(celsius+273.15))/(2*FARADAY) * log (cao/cai)
	iCa = gcatbar*m*m*h*(v-eca)	: dummy calcium current induced by this channel
:	ica = gcatbar*m*m*h*(v-eca)	: dummy calcium current induced by this channel

}

FUNCTION ghk(v(mV), ci(mM), co(mM)) (.001 coul/cm3) {
	LOCAL z, eci, eco
	z = (1e-3)*2*FARADAY*v/(R*(celsius+273.15))
	eco = co*efun(z)
	eci = ci*efun(-z)
	:high cao charge moves inward
	:negative potential charge moves inward
	ghk = (.001)*2*FARADAY*(eci - eco)
}

FUNCTION efun(z) {
	if (fabs(z) < 1e-4) {
		efun = 1 - z/2
	}else{
		efun = z/(exp(z) - 1)
	}
}


DERIVATIVE states {
	rates(v)
	m' = (minf -m)/tm0
	h'=  (hinf - h)/th0
}


PROCEDURE rates(v (mV)) { 
        LOCAL a, b
        
	a = alpm(v)
	minf = 1/(1+a)
        
        b = alph(v)
	hinf = 1/(1+b)
}



FUNCTION alpm(v(mV)) {
UNITSOFF
  alpm = exp(1.e-3*zetam*(v-vhalfm)*9.648e4/(8.315*(273.16+celsius))) 
UNITSON
}

FUNCTION alph(v(mV)) {
UNITSOFF
  alph = exp(1.e-3*zetah*(v-vhalfh)*9.648e4/(8.315*(273.16+celsius))) 
UNITSON
}


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