Distinct current modules shape cellular dynamics in model neurons (Alturki et al 2016)

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Accession:223649
" ... We hypothesized that currents are grouped into distinct modules that shape specific neuronal characteristics or signatures, such as resting potential, sub-threshold oscillations, and spiking waveforms, for several classes of neurons. For such a grouping to occur, the currents within one module should have minimal functional interference with currents belonging to other modules. This condition is satisfied if the gating functions of currents in the same module are grouped together on the voltage axis; in contrast, such functions are segregated along the voltage axis for currents belonging to different modules. We tested this hypothesis using four published example case models and found it to be valid for these classes of neurons. ..."
Reference:
1 . Alturki A, Feng F, Nair A, Guntu V, Nair SS (2016) Distinct current modules shape cellular dynamics in model neurons. Neuroscience 334:309-331 [PubMed]
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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: Hippocampus; Amygdala;
Cell Type(s): Abstract single compartment conductance based cell;
Channel(s):
Gap Junctions:
Receptor(s):
Gene(s):
Transmitter(s):
Simulation Environment: NEURON;
Model Concept(s): Simplified Models; Activity Patterns; Oscillations; Methods; Olfaction;
Implementer(s):
/
AlturkiEtAl2016
2_Pospischil
Original
README.html *
cadecay_destexhe.mod *
HH_traub.mod *
IL_gutnick.mod
IM_cortex.mod
IT_huguenard.mod
demo_IN_FS.hoc *
demo_PY_IB.hoc *
demo_PY_IBR.hoc *
demo_PY_LTS.hoc *
demo_PY_RS.hoc *
fig5b.jpg *
mosinit.hoc *
rundemo.hoc *
sIN_template *
sPY_template *
sPYb_template *
sPYbr_template *
sPYr_template *
                            
TITLE Low threshold calcium current
:
:   Ca++ current responsible for low threshold spikes (LTS)
:   THALAMOCORTICAL CELLS
:   Differential equations
:
:   Model based on the data of Huguenard & McCormick, J Neurophysiol
:   68: 1373-1383, 1992 and Huguenard & Prince, J Neurosci.
:   12: 3804-3817, 1992.
:
:   Features:
:
:	- kinetics described by Nernst equations using a m2h format
:	- activation considered at steady-state
:	- inactivation fit to Huguenard's data using a bi-exp function
:	- shift for screening charge, q10 of inactivation of 3
:
:
:   Written by Alain Destexhe, Salk Institute, 1993; modified 1995
:

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

NEURON {
	SUFFIX it
	USEION ca READ cai,cao WRITE ica
	GLOBAL q10
	RANGE gcabar, m_inf, tau_m, h_inf, tau_h, shift, i
}

UNITS {
	(molar) = (1/liter)
	(mV) =	(millivolt)
	(mA) =	(milliamp)
	(mM) =	(millimolar)

	FARADAY = (faraday) (coulomb)
	R = (k-mole) (joule/degC)
}

PARAMETER {
	v		(mV)
	celsius	= 36	(degC)
	gcabar	= 0.002	(mho/cm2)
	q10	= 3			: Q10 of inactivation
	shift	= 2 	(mV)		: corresponds to 2mM ext Ca++
	cai	= 2.4e-4 (mM)		: adjusted for eca=120 mV
	cao	= 2	(mM)
}

STATE {
	h
}

ASSIGNED {
	ica	(mA/cm2)
	i 	(mA/cm2)
	carev	(mV)
	m_inf
	tau_m	(ms)			: dummy variable for compatibility
	h_inf
	tau_h	(ms)
	phi_h
}

BREAKPOINT {
	SOLVE castate METHOD cnexp
	carev = (1e3) * (R*(celsius+273.15))/(2*FARADAY) * log (cao/cai)
	ica = gcabar * m_inf * m_inf * h * (v-carev)
	i = ica
}

DERIVATIVE castate {
	evaluate_fct(v)

	h' = (h_inf - h) / tau_h
}


UNITSOFF
INITIAL {
	h = 0

:
:   Transformation to 36 deg assuming Q10 of 3 for h
:   (as in Coulter et al., J Physiol 414: 587, 1989)
:
	phi_h = q10 ^ ((celsius-24 (degC) )/10 (degC) )
}

PROCEDURE evaluate_fct(v(mV)) { LOCAL Vm

	Vm = v + shift

	m_inf = 1.0 / ( 1 + exp(-(Vm+57)/6.2) )
	h_inf = 1.0 / ( 1 + exp((Vm+81)/4.0) )

:	if(Vm < -80) {
:		tau_h = exp((Vm+467)/66.6) / phi_h
:	} else {
:		tau_h = ( 28 + exp(-(Vm+22)/10.5) ) / phi_h
:	}

	tau_h = 30.8 + (211.4 + exp((Vm+113.2)/5)) / (1 + exp((Vm+84)/3.2))

	tau_h = tau_h / phi_h

}

UNITSON