Zebrafish Spine (video) Northwestern University Loading video... Caption Motor neurons in the larval zebrafish spinal cord (the tube-shaped structure near the top) send out axons to innervate the segmented body muscles that generate swimming (side-on view). Because the fish are transparent, the nerves can be visualized in living fish using proteins that can glow in the dark. Credit McLean lab, Northwestern University Usage Restrictions The inclusion of an institutional credit is required. 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.