Concentration Gradient (IMAGE) Nara Institute of Science and Technology Caption A slight concentration gradient (0.4 percent) in netrin-1 (blue) induces a 71 percent difference in shootin1a phosphorylation (green) within growth cones. Credit Naoyuki Inagaki 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.