Voltage clamp with stochastic channels. There are four cases varying in
the density of channels in the model (from 2 or
to 16 per square micron). Each case is run 400 times of which six are
shown in the default plots. The mean variance analysis operates on the
5-10 ms time window and shows the variance against the mean current. The form
should be a parabola, with the slope at the origin giving the single channel
conductance and the intercept on the X axis the total number of channels.