A simple two-neuron network

The goal of this exercise is to create a simple network of two cells that
fire in alternate bursts.  To make it easy to get started, you have been
given all of the scripts to create a simulation with a single cell:

simplecell.g - creates a simple cell with a soma and a dendritic compartment
cell.p  - the cell parameter file for the cell, used by the readcell command
protodefs.g - makes the prototypes for the channels, compartments, and spike
    generator that readcell creates from the cell parameter file
graphics.g - provides the GUI for the simulation
xtools.g - defines some script functions that are usefull for making GUIs

The main script simplecell.g uses the readcell command to create the cell
"cell1" from the cell parameter file, cell.p.  Chapter 16 of the Book of
GENESIS (BoG) and the documentation for the readcell command explain the
details of creating a cell from a cell parameter file.  The file
protodefs.g, which is included by simplecell.g, includes files that are in
the Scripts/neurokit/prototypes directory.  This is possible because your
.simrc file gives a path to that location.  These files define the
functions used by protodefs.g to create the elements that are named in the
cell.p file.  Finally, the graphical user interface is provided by the file
grpahics.g.  Most of the XODUS commands used in this file are explained in
BoG chapters 13 and 14.  The "scale" button in the upper left corner of the
graph is made with the "makegraphscale" function that is defined in
xtools.g.

The resulting cell has a soma compartment with squid-like Na and K
channels, and a dendrite compartment with both an excitatory and an
inhibitory synaptically activated channel, implemented with synchans.  The
soma receives a default injection current of 0.5 nA, and fires a regular
train of spikes, much like the single compartment example in BoG chapter
14.

Spend some time running the simplecell simulation and understanding enough
of the simulation scripts until you feel that you are ready to modify
simplecell.g to make two coupled cells.  Then, copy these files into your
own directory, and make the changes necessary to create a second cell with
no current injection, and plot its Vm on the graph in a different color.
Of course, the plot will be a flat line, as it is receiving no stimulus.
Now, use the information in BoG chapter 15 or the docmentation for synchan
to connect the spike output of cell1 to the excitatory synchan of cell2,
and the spike output of cell2 to the inhibitory input of cell1.  Use an
axonal propagation delay of 0.005 seconds for each connection.  Finally,
experiment with the synaptic weights for each synapse until you can achieve
a pattern of alternate bursts of action potentials.  To make it easy to
change the weights, you may wish to add dialog boxes for entering weights
to the control panel.

