Model files from the paper: M. Migliore, Modeling the attenuation and failure of action potentials in the dendrites of hippocampal neurons, Biophys. J. 71:2394-403 (1996). The paper proposed (and experiments later confirmed) a slow inactivation of the Na channels as the mechanism responsible for the progressive reduction of action potentials amplitude, observed in the dendrites of CA1 hippocampal pyramidal neurons during a train. This mechanism was modeled using an additional gate variable in the Na+ conductance. The gate variable and its kinetics are now included in the updated Na+ conductance (na3.mod) of the 1999 CA1 model. Under unix systems: =================== to compile the mod files use the command nrnivmodl and run the simulation hoc file with the command nrngui figs.hoc Under Windows: ============== to compile the mod files use the "mknrndll DOS box" and follow on-screen instructions. A double click on the simulation file figs.hoc will open the simulation window. This CA1 model can be used to run three related simulations, corresponding to the simulations shown in Fig.3 (right), Fig.4bc, and Fig.4bd of the paper. "run Fig.3" will show somatic and dendritic membrane potential during a 450ms suprathreshold dendritic current injection on a distal compartment, followed by a 70ms current pulse after a 250ms delay. To demonstrate the recovery from slow inactivation, "run Fig.4bc" will show membrane potential of a distal compartment from 4 overlapping simulations with the same initial 450ms dendritic current injection followed by a short 70 pulse after different delays. To demonstrate that hyperpolarization increases the rate of recovery as observed in the experiments,"run Fig.4bd" will show the same simulation as in "run Fig.3", but with a -0.5nA dendritic current injection during the 250ms delay. Questions on how to use this model should be directed to michele.migliore@pa.ibf.cnr.it