A plaque is an abnormal cluster of protein fragments. Such clusters can be found between nerve cells in the brain of someone with Alzheimer. A microscope will also show damaged nerve cells. In them are tangles called neurofibrillary tangles. These consist of twisted strands of a different protein.
Together, the plaque and tangles cause structural and chemical problems. It appears that Alzheimer disease causes parts of the brain that normally work together to disconnect.
Review Date 2/4/2020
Updated by: Amit M. Shelat, DO, FACP, FAAN, Attending Neurologist and Assistant Professor of Clinical Neurology, Stony Brook University School of Medicine, Stony Brook, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.