News Neuroscience

Ancient viruses helped speedy nerves evolve

The trick happened multiple independent times in jawed animals

Stacks of long tubes of various lengths are seen. Inside the tubes is a bright purple "filling". This is the long part of a nerve fiber called an axon. Around those fibers are thick tubes colored brownish-gray that form an insulating sheath around the nerve. Some wispy strands of connective tissue lays over some of the tubes. Connective tissue is colored hot pink.

An ancient virus may help myelin (grayish brown) form a sheath around nerve fibers (purple), as shown in this colored scanning electron micrograph of a broken bundle of nerves. Connective tissue (pink) encases the nerve fibers.

Steve Gschmeissner/Science Photo Library/Getty Images Plus

By Tina Hesman Saey

Ancient viruses have really gotten on our nerves, but in the best of ways.