Researchers at the Albert Einstein College of Medicine believe that a decline in the number of neural stem cells in the hypothalamus is one of the major causes for aging. The hypothalamus is involved in regulation of hormone-secreting glands, metabolism, growth and plays an important role in maintaining the general health and stability of the body (homeostasis). In an animal model, by replenishing the supply of stem cells in the hypothalamus, researchers delayed the noticeable and deteriorating effects of aging. The study involved two phases to test the researcher’s hypothesis. The first phase involved taking one group of “middle-aged” mice and decreasing the supply of stem cells in the hypothalamus and comparing them to a control group where no manipulation took place. The manipulated group exhibited quicker deterioration and displayed palpable signs of aging compared to the control group, suggesting that the number of stem cells present in the hypothalamus is linked to the aging process. In the second phase of the study, a manipulated group received additional stem cells. In comparing this manipulated group to the control group, the manipulated group exhibited a slowing of the aging process as a result of the addition of stem cells. Therefore, when the number of stem cells was increased rather than decreased, the mice showed a slower progression of age related deterioration over their lifespan.