A network model of the vertebrate retina (Publio et al. 2009)

 Download zip file   Auto-launch 
Help downloading and running models
Accession:124063
In this work, we use a minimal conductance-based model of the ON rod pathways in the vertebrate retina to study the effects of electrical synaptic coupling via gap junctions among rods and among AII amacrine cells on the dynamic range of the retina. The model is also used to study the effects of the maximum conductance of rod hyperpolarization activated current Ih on the dynamic range of the retina, allowing a study of the interrelations between this intrinsic membrane parameter with those two retina connectivity characteristics.
Reference:
1 . Publio R, Oliveira RF, Roque AC (2009) A computational study on the role of gap junctions and rod Ih conductance in the enhancement of the dynamic range of the retina. PLoS One 4:e6970 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism:
Cell Type(s): Retina ganglion GLU cell; Retina photoreceptor cone GLU cell; Retina bipolar GLU cell;
Channel(s):
Gap Junctions: Gap junctions;
Receptor(s):
Gene(s):
Transmitter(s): Glutamate;
Simulation Environment: NEURON;
Model Concept(s): Sensory processing;
Implementer(s): Publio, Rodrigo [publio at oist.jp];
Search NeuronDB for information about:  Retina ganglion GLU cell; Retina photoreceptor cone GLU cell; Retina bipolar GLU cell; Glutamate;
/
PublioEtAl2009
README.html
A2hh_k.mod
A2hh_na.mod
Bip_Ca.mod
Bip_Cad.mod
Bip_ih.mod
Bip_Ka.mod
Bip_Kv.mod
Cone_CPR.mod
Cone_ih.mod
Cone_Kv.mod
Ganglion_hh.mod *
gap.mod
IinjLT.mod
IinjLT_cone.mod
IinjLTDim.mod *
Rod_Ca.mod
Rod_Cad.mod
Rod_Clca.mod
Rod_ih.mod
Rod_Kca.mod
Rod_Kv.mod
Rod_Kx.mod
Rod_leak.mod
syn_bip_gan.mod
syn_rod_bip.mod
A2.tem
Bip.tem
Cone.tem
createcells.hoc
Ganglion.tem
gap.hoc *
init.hoc
mosinit.hoc *
netconnection.hoc
parameters.hoc
Rod.tem
screenshot1.jpg
screenshot2.jpg
session.ses
                            
COMMENT
Internal calcium concentration calculated in response to a calcium current calculated elsewhere,
and a single-exponetial extruding pump calculated here. Valid for small distances from the membrane,
where the suface to volume ratio of a cylinder can be approximated as 1/depth .
This code was modified from Destexhe,Babloyantz & Sejnowski (Biophys. J. 65(1993): 1538-1552 --Equ. 7 ) 
ENDCOMMENT

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

NEURON {
	SUFFIX cad
	USEION ca READ ica, cai WRITE cai
	RANGE depth,cainf,taur
}

UNITS {
	(molar) = (1/liter)			: moles do not appear in units
	(mM)	= (millimolar)
	(um)	= (micron)
	(mA)	= (milliamp)
	(msM)	= (ms mM)
}

CONSTANT {
	FARADAY = 96489		(coul)		: moles do not appear in units
}

PARAMETER {
	depth	= 10	(um)		: depth of shell, was 0.1
	taur	= 20	(ms)		: remove first-order decay was 1.5
	cainf	= 0.00005 (mM)
}

STATE {
	cai		(mM) 
}

INITIAL {
	cai = 0.0001
}

ASSIGNED {
	ica		(mA/cm2)
	drive_channel	(mM/ms)
	drive_pump	(mM/ms)
}
	
BREAKPOINT {
	SOLVE state METHOD derivimplicit
}

DERIVATIVE state { 

: Surface to volume ratio of a cylinder is approximated as 1/depth for very small values of depth
: More precicely the ratio is   2 / ( (depth)^2 / (diam/2 - (2 * depth)) )

	drive_channel =  - (10000) * ica / (2 * FARADAY * depth)

	if (drive_channel <= 0.) { drive_channel = 0. }	: cannot pump below resting level
	cai' = drive_channel + (cainf-cai)/taur
}


Loading data, please wait...