Cells (IMAGE) University of Bonn Caption In healthy mice, the insulating myelin (black) fits snugly as a compact layer around the nerve fibers, the axons. Credit © Group Prof. Kürten/University of Bonn Usage Restrictions Please use this image only in connection with the press release. 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.