A new bioluminescence imaging technique has created highly detailed, and visually striking, images of the movement of oxygen in the brains of mice. The method, which can be easily replicated by other labs, will enable researchers to more precisely study forms of hypoxia in the brain, such as the denial of oxygen to the brain that occurs during a stroke or heart attack. The new research tool is already providing insight into why a sedentary lifestyle may increase risk for diseases like Alzheimer's.