In Panel A:
A normal Myelinated Axon, the Action Potential (dashed arrow) travels, with high velocity and reliability, to the PostSynaptic Neuron.

In Panel B:
Conduction is blocked in (black bar), acutely DeMyelinated Axons.

In Panel C:
Conduction is restored in some chronically DeMyelinated Axons that acquire a higher-than-normal density of Sodium channels.

In Panel D:
Axonal degeneration, by contrast, permanently interrupts Action-Potential propagation.

Copyright © 1998 by the Massachusetts Medical Society. All rights reserved.