Senile plaques and Alzheimer's disease

Professor Kenneth Kosik describes senile plaques, an extracellular collection of a-beta protein. It is one of the hallmarks of Alzheimer's disease.

As many people now are aware, the classical stigmata of Alzheimer’s disease, the classical hallmarks, are plaques and tangles. The senile plaque is an extracellular collection of protein. It’s a protein that is referred to as the a-beta. It’s a fragment of a normal protein we all have called the amyloid precursor protein. It gets chopped into a smaller piece called a-beta that then collects, assembles outside of cells, and forms this aggregate mass that forms a ball between the neurons, between the interstices of the brain, and pushes aside all of the fine ramifications and connections of brain cells to form what we call a plaque.