Aging Nerves (IMAGE) Society for Neuroscience Caption Immune cells may contribute to weakness and mobility issues in the elderly by driving nerve degeneration. Nerve fibers of normal adult animals (e.g., 12 months of age) consist of an axon (brown), and a Schwann cell (blue) forming a myelin sheath (black ring) around the axon. Few harmless, non-activated macrophages (red) neighbor the fibers. During aging (blue arrows), myelin rings slightly change their shape, concommitant with an activation of macrophages. These macrophages remove the myelin sheathes, resulting in no or thin myelin and disturbed nerve function. When macrophages are deleted (green arrow), the aging myelin sheath is rescued and function preserved. Pink profiles represent cell nuclei. Credit Rudolf Martini 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.