Motor Neuron Growth (IMAGE) Salk Institute Caption Left: Motor neurons (green) exit the spinal cord (red) and enter the periphery of the body to connect with muscles. Right: Motor neurons (white arrow) without the guidance of p190 are trapped within the spinal cord. Credit Salk Institute Usage Restrictions with credit and related coverage. 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.