Axons (IMAGE) University of Wisconsin-Madison Caption In the normal nerve (a) all axons in the optic nerve are surrounded by thick, dark sheaths of myelin in contrast to the completely demyelinated nerve (b) during active disease (when VEP latency lengthens). After recovery (in c) axons have been remyelinated--and though the sheaths are thin compared to normal, the VEP latency has shortened. Credit Ian Duncan Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.