Science image (IMAGE) Salk Institute Caption In the image on the left, motor neurons (green) clear a path through blood vessels (red) as they grow toward muscles in developing healthy mice. On the right, this process is disrupted in mice where genetic mutation prevents the blood vessels from detecting signals that tell them to move out of the way. Credit Salk Institute Usage Restrictions with credit and related coverage. License Original 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.