Axon guidance is the pathfinding step that enables axons—the longest part of a neuron, through which the nerve impulse is propagated ... However, the underlying mechanisms were not yet fully ...

An electrical impulse cannot directly cross the gap so a different mechanism has to be used.

Dopamine is one of many types of neurotransmitter -- chemical signals that one neuron launches at its neighbor to trigger a nerve impulse. “Of all the neurotransmitters ... not by any means proven ...

Although the exact mechanism of action is unclear ... to a hand held nerve stimulator which sends an electrical impulse to the nerve. This nerve impulse is then transmitted to the sacral plexus ...