A traveling nerve impulse does not depolarize the area immediately behind it, because:
When an AP is initiated at a point, the point goes into refractoriness when the Na+ entered through that point has excited the adjacent (2nd) point. so it will travel in single direction Hyperpolarization event is after the refractory period.
It is hyperpolarised
It is refractory
It is not self-propagating
The conduction is always ohodromic
Excitation and Action Potiential