NEURON mod files from the paper: Computational simulation of the input-output relationship in hippocampal pyramidal cells by Xiaoshen Li, Giorgio A. Ascoli Journal of computational neuroscience, In press The model shows how different input patterns (irregular & asynchronous, irregular & synchronous, regular & asynchronous, regular & synchronous) affect the neuron's output rate when 1000 synapses are distributed in the proximal apical dendritic tree of a hippocampus CA1 pyramidal neuron. It shows four different input frequencies (1 Hz, 4 Hz, 7 Hz and 10 Hz) as shown in the paper fig5A. In the irregular input cases (irregular asynchronous and irregular synchronous), because the random number generated is dependent on the seed and the seed is dependent on the simulation environment, the simulation gives different spiking traces on each run. For the long simulation period (2 seconds), the overall output frequency is constant and is only related to the input frequency. Under unix systems: to compile the mod files use the command nrnivmodl and run the simulation hoc file with the command nrngui mosinit.hoc Under Windows systems: to compile the mod files use the "mknrndll" command. A double click on the simulation file mosinit.hoc will open the simulation window. Questions on how to use this model should be directed to xsli2@yahoo.com