This is the readme for the model associated with paper:

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(9): e6970. doi:10.1371/journal.pone.0006970  

These NEURON model files were contributed by Rodrigo Publio.

Recent works suggest that one of the roles of gap junctions in sensory
systems is to enhance their dynamic range by avoiding early saturation
in the first processing stages. 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. Our results show that for
realistic values of Ih conductance the dynamic range is enhanced by
rod-rod coupling, and that AII-AII coupling is less relevant to
dynamic range amplification in comparison with receptor
coupling. Furthermore, a plot of the retina output response versus
input intensity for the optimal parameter configuration is well fitted
by a power law with exponent ~0.5. The results are consistent with
predictions of more theoretical works and suggest that the earliest
expression of gap junctions along the rod pathways, together with
appropriate values of rod Ih conductance, has the highest impact on
vertebrate retina dynamic range enhancement.  ~

Figures 1 of "A Computational Study on the Role of Gap Junctions and
Rod Ih Conductance in the Enhancement of the Dynamic Range of the
Retina" can be replicated with this code, for example:




After compiling all MOD files load the appropriate HOC file (init.hoc)
from the neuron main menu after starting nrngui or by either double
clicking in mswin's window explorer, typing nrngui init.hoc in unix,
or dragging and dropping the init.hoc file onto the nrngui icon in Mac
OS X. Session files are called by the main HOC file.

The network dimensions and synaptic convergence/divergence are
specified at the parameters.hoc file. The cells are created from
templates at the createcells.hoc while gap junctions and chemical
synapses are created at netconnection.hoc.

20120326 Bip_Cad.mod and Rod_Cad.mod solve methods updated from euler
to derivimplicit as recommended in 
http://www.neuron.yale.edu/phpbb/viewtopic.php?f=28&t=592