Understanding the physiology of Alzheimer’s disease is a work in progress for medical researchers. Research conducted over the past two decades by Dennis Selkoe, MD, at Brigham and Women’s Hospital has shown that buildup in the brain of a protein called amyloid-beta is largely responsible for the degenerative effects of the disease, but there is still much to be learned. What is known is that amyloid-beta forms plaques and clumps, inhibiting the brain’s neurons and damaging their connections to one another. Other researchers are investigating the role of a protein called tau which causes tangles inside nerve cells, leading to the cells’ death.