This is an alternative implementation of:

Fleidervish IA, Lasser-Ross N, Gutnick MJ, Ross WN (2010) Na+ imaging reveals little difference in action potential-evoked Na+ influx between axon and soma. Nat Neurosci 13:852-60. doi:10.1038/nn.2574.

The author's version is available at http://modeldb.yale.edu/136715.

The main differences are:

The original was implemented mostly using NEURON's gui tools with a little HOC; this version is implemented in a Python script for NEURON.
The original uses a MOD file to handle sodium accumulation and diffusion; this version use NEURON's reaction-diffusion support.
The original has two additional simulations using a reduced model with no dendrites.

Two of the three mod files used (kv, Kv1) have been retained unmodified from the author's version. The third, nacurrent is a simplified version of the original author's hh_Cs_scaled after removing the potassium and leak currents from that file which are not used in this model. The name has been changed to deemphasize the file's historical connection to hh.mod as the temperature dependence and rate functions are not intended to be appropriate for modeling a squid.

To run, compile the mod files in this directory (on Linux or Mac by changing to this directory and typing nrnivmodl; on Windows by dragging this folder to the mknrndll icon), then run mosinit.py via either:
python -i mosinit.py
or
python3 -i mosinit.py
depending on your Python setup. Choose either "Fig 3A" or "Fig 6B" from the popup, and click "Init & Run". When the simulations complete you should see the respective images below:

Fig 3A:

Fig 6B: