Cognitive impairment and a build-up of abnormal proteins in the brain are better known tell-tale signs of Alzheimer's disease, but other clues may reveal its presence earlier in the piece. Among those is a reduced blood flow to the brain, and scientists from Cornell University believe they have now found an explanation for these blockages, raising new hopes for treatments that target one of the disease's potential root causes.

Just like elsewhere in the body, blood flow into the brain is essential for delivering the oxygen and nutrients needed for cells to do their job properly. When something stems that flow, it can impact cognitive functions like learning and memory, and decades of research has linked this process with the two leading causes of dementia, Alzheimer's disease and vascular dementia.

Pinpointing the exact mechanisms at play would provide invaluable new targets for dementia therapies, but they remain the source of much conjecture. Recent research has pointed to a breakdown in the blood-brain barrier as a factor, for example, with a study published in Neuron last week suggesting leaks allow toxic blood-clotting proteins to gain access and trigger synaptic damage.

A new paper from medical scientists at Cornell University puts forward another explanation. The research stemmed from the discovery of blood clots in the brains of mice with Alzheimer's. More specifically, the researchers found white blood cells were adhering to the inside of capillaries, the brain's smallest blood vessels.