Use the Hodgkin-Huxley model (equations and parameters from Hoppensteadt) for the nerve action potential to estimate the following:
a) The voltage threshold for excitation
b) The current threshold for excitation
c) The refractory period for stimulation with a current of 10 uA and duration 1 ms
d) The relationship of the frequency of action potentials to the strength of a continuous stimulatory current.