NEURON mod files from the paper: M. Migliore, On the integration of subthreshold inputs from Perforant Path and Schaffer collaterals in hippocampal CA1 pyramidal neurons, J.Comput. Neurosci., in press (2002). The model shows how the experimentally observed increase in the dendritic density of Ih and IA could have a major role in constraining the temporal integration window for the main CA1 synaptic inputs. The main effect is demonstrated here for a subset of conditions from fig.4 of the paper, which is the result of long simulations. With the fig4.hoc file three series of simulations will run. In all cases, two synapses in a proximal and distal compartment will be activated at latencies between -30 and 18ms. The three cases differ for the dendritic distribution of gKA and Ih. - full model, with gKA and Ih increasing with distance from soma - uniform KA, with constant gKA and increasing Ih. - uniform KA and Ih, with constant gKA and constant Ih. The top simulation panel shows the membrane potential at the soma during each simulation. In the bottom panel a circle will be shown at the end of each simulation. The circle will be filled if an Action Potential was generated by the simulation. The simulations are intended to demonstrate how the temporal window for summation of the two inputs to elicit an AP is affected by the experimentally observed dendritic gKA and Ih distribution. Under unix systems: to compile the mod files use the command nrnivmodl and run the simulation hoc file with the command nrngui fig4.hoc Under Windows systems: to compile the mod files use the "mknrndll" command. A double click on the simulation file fig4.hoc will open the simulation window. Questions on how to use this model should be directed to michele.migliore@pa.ibf.cnr.it Bugs and fixes: 04 July 2003 - M. Migliore A bug in the vhalfl variable declaration in h.mod required a change of ghd in fig4.hoc (from 0.0002 to 0.0005) to obtain the same results.