(IMAGE) University of Cologne Caption Nerve cells of a mouse brain (green) and the protein PRG-1 (red). If the nerve cells contain PRG-1, the cells appear in yellow. Credit Johannes Vogt Usage Restrictions none 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.