NPB 112 - Neuroscience Propogation of the action potential. Upper drawing shows an unmyelinated axon. Current flows down the path of least resistance, mainly in the axoplasm, but some current also flows down low-resistance paths out of the cell. This means that the action potential decreases in voltage as it moves down the axon.
Lower drawing shows a myelinated axon.
The myelin prevents any current from leaving the axon.