Getting older is the biggest risk factor for developing ALS, but scientists have never fully understood exactly how the normal aging process interacts with the disease. To figure this out, researchers created a highly detailed, lifelong map of the spinal cord, comparing the individual cells of healthy mice to those with an ALS-like condition. They discovered that different sections of the spinal cord react to the disease differently, which explains why the lower spine tends to break down much faster than the neck area. Long before any physical symptoms even started, researchers noticed that the natural “waste disposal” system inside the cells of those vulnerable areas had already begun to fail. Interestingly, they also found that having ALS doesn’t just cause the entire spinal cord to age faster. Instead, only the nervous system’s dedicated immune cells showed signs of rapid, unnatural aging. Ultimately, this comprehensive lifelong map helps explain exactly how the normal aging process collides with hidden cellular damage to trigger the devastating effects of ALS.