NEURON mod files from the paper:
Mercer JN, Chan CS, Tkatch T, Held J, Surmeier DJ. Nav1.6 sodium
channels are critical to pacemaking and fast spiking in globus
pallidus neurons.,J Neurosci. 2007 Dec 5;27(49):13552-66.
This is the model demonstrated in Figures 9.B-C & 10.A-B:
Figure 9. Two Na+ channel model of wild-type and Nav1.6 null
neurons. B, Voltage records from a representative GPe neuron were used
as voltage commands to estimate the availability (as sum of channels
in the O and C1–5 states) of model Na+ channels. Action potentials
were truncated for clarity. C, Steady-state availability of modNav1.1
(red) and modNav1.6 (blue) channels during basal autonomous firing at
12 Hz (left), as well as that during driven activity (with
intracellular current pulses) at 50 Hz.
Figure 10. Simulations suggest that Nav1.6 channels are critical to
fast spiking but not pacemaking. A, Autonomous activity in a model of
a GPe neuron. Top trace, Spiking of the model wild-type neuron at 12
Hz when the complete complement of Na+ channels is present. Middle
trace, Spiking of the model neuron is reduced to 5 Hz when model
Nav1.6 channels are simply deleted from the model. Bottom trace,
Spiking of the model neuron is restored to near that of the wild-type
model when Na+ channel density is maintained by replacing model Nav1.6
channels with model Nav1.1 channels. B, The response of the same three
models to a current ramp delivered to the soma. In the wild-type
model, the maximum discharge rate was near 100 Hz. In contrast, the
model in which Nav1.6 channels were deleted failed to fire at a high
frequency (middle); maintaining Na+ channel density by replacing
Nav1.6 channels improved the performance of the model, but the peak
discharge rate was still well below that of the wild-type model with
modNav1.6 channels (bottom).
Sample model usage: (Note, you will have re-launch the model between
running Figure 9 & 10, and vice versa.)
Figure 9 - The run includes a period of autonomous firing at about 12
Hz followed by a period of driven activity at about 50 Hz.
Figure 10 - The run includes a current injection ramp of 1 nA over the
last 1 second. The data in the figure are based on the steady state
condition before the ramp.
To delete the Nav1.6 channels, use the "Remove Na1.6" button. To
replace Nav1.6 channels with Nav1.1 channels, use the "Replace Na1.6"
Questions on how to use this model can be directed to Josh Held,