Main simulation script: FScell.g
Model description:
This simplified neuron model could be used to represent a fast spiking interneuron in a cortical network. However, the model was created to provide an example of GENESIS scripting, rather than to fit the current clamp firing patterns of typical cortical inhibitory interneurons. Some parameter adjustments are likely to be necessary before it is used in a realistic cortical network model. The single-compartment RScell model with the muscarinic current removed would also be a good starting point for a parameter search over passive cell parameters and the conductance densities for the Na and K currents.
The main script FScell.g uses the cell reader to create a simple two-compartment neuron with a dendrite compartment, a soma, and an axon. The dendrite contains synaptically activated excitatory and inhibitory channels and the soma contains "squid-like" voltage-activated Hodgkin-Huxley sodium and potassium channels, plus a spikegen element that acts like the intial part of an axon. This may be used to provide synaptic input to another cell.
The simulation is based on an example script to create a neuron from a specified cell parameter file, with channels taken from the prototypes created by the file protodefs.g. It can be customized for another cell by changing strings that are defined in the main script, providing a cell parameter file for the new cell, and providing a modified protodefs.g file to create the necessary prototype elements. When used with the GUI functions defined in graphics.g, it allows a an injection current and a variety of synaptic inputs to be applied.
The CONTROL PANEL of the GUI (defined in graphics.g) allows a steady injection current to be applied to the cell, and/or synaptic activation to be applied to the synchan that is specified in the string variable 'synpath'. If the value of synpath is '' (empty), then the synaptic input form does not appear.
In the synaptic input form, 'gmax' is used to set the gmax field of the specied synchan. Poisson-distributed background activation can be applied to the synchan by setting the 'Frequency' (the average activation frequency) to a non-zero value. This sets the frequency field of the synchan to that value. The 'Spike input ON/OFF' toggle turns on and off the application of trains of spikes at the specified 'Spike interval'.
The scripts in this directory are:
README This file.
FScell.g The main simulation script to start the simulation.
cell.p The cell parameter file for the model
protodefs.f File to create the library of prototype channels and other
elements used by the cell parameter file.
graphics.g A generic GUI to control the simulation. It can be somewhat
customized by setting the value of parameters and strings
the main simulation script.
These scripts are used as an example in:
Bower, J. M. and Beeman, D. (2007) Constructing Realistic Neural Simulations with GENESIS. In: Methods in Molecular Biology, vol. 401: Neuroinformatics, (C. Crasto, ed.) Humana Press, Totowa, NJ, Chapter 7, pp. 103-125.