Science image (IMAGE) Salk Institute Caption Shell neurons (green) that project to the breathing center and core neurons (red) that project to the pain/emotion center. 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.