New insights on what causes Alzheimer's disease could arise from a recent discovery made by bioengineers. The finding concerns the infamous amyloid beta peptides (A²) -- fragments of which form plaques thought to play a role in Alzheimer's disease. The bioengineers found that amyloid beta peptides spontaneously trigger calcium waves in purified cultures of astrocyte cells extracted from the cortex region of rat brains and grown in the lab.