Motor Neurons in a Fly Embryo (IMAGE) Johns Hopkins Medicine Caption As fruit flies develop, motor neurons (green) extend from either side of their spinal-cord-like structures (left) to connect to muscle fibers (red), branching as they go. Credit Zhuhao Wu 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.