Stem cells in the brain are located in the hypothalamus, which produces hormones and other signalling molecules. Prior research has provided evidence suggesting that the hypothalamus is involved in aging. A new breakthrouogh research study conducted by researchers at Albert Einstein College of Medicine in New York City finds that these special cells in the hypothalamus disappear as mice grow older. The researchers injected the mice with viruses that destroy the cells and observed that the animals grew older faster and experienced declines in memory, muscle strength, endurance and coordination. These mice also died sooner than untreated mice. When stem cells from newborn mice were injected into the brains of middle-aged mice, the older mice over a period of months displayed better cognitive and muscular function than untreated mice of the same age and also lived about 10% longer, on average.