Excitation propagation in septated axons

The impulse propagation in septated nerve fiber is considered. The points of investigation are: excitation propagation velocity as a function of time and nerve fiber parameters; and the critical value of electrical resistance of septum above which the excitation propagation becomes impossible. The velocity of impulse propagation was found for small values of septum resistance. It was shown that average velocity of impulse propagation in septated axon equals that in a uniform fiber with axoplasmic resistance including resistance of septae. septa. obtained value of critical resistance differs significantly from the results of stationary estimations. This depends on the ratio of the duration of sodium current to the characteristic membrane time. Theoretical results are compared with experiments on the crayfish giant septated axon.