Moore, Stockbridge, and Westerfield. (1983) On the site of impulse initiation in a neurone. J. Physiol. 336: 301-311. This model qualitatively reproduces figures 1-5. Note that orthodromic stimulus amplitude is considerably different from that noted in the paper. IClamp[0].amp was chosen to give qualitative similarity. We attribute minor quantitative differences to the following: 1) The precise site of axon v vs t curve is not specified. We plot axon.v(0.25). 2) The antidromic stimulus was unspecified. The NEURON implementation of this model was prepared by Michael Hines. Questions about details of this implementation should be addressed to him at michael.hines@yale.edu.