Alzheimer's disease has long been studied primarily as a disease of neurons. But researchers have now shown how the disease may be damaging the brain by choking off blood flow. Scientists have revealed that amyloid-², which builds up around brain cells in Alzheimer's patients, interacts with a common blood clotting agent to increase clotting in the arteries that feed the brain. Such activity could cut off blood flow to neurons, suffocating them over time.