PET Scans (image) University of California - Berkeley Share Print E-Mail Caption Shown are PET scans that track tau (top row) and beta-amyloid from two normal older people and a patient with Alzheimer's disease (AD). The normal older adult on the left has no brain amyloid deposition and minimal tau in the medial temporal lobe. In the normal older adult in the middle, amyloid deposition is present throughout the brain, and tau has spread out into the temporal cortex. In the AD patient, both amyloid and tau are spread through the brain. Credit Image by Michael Schöll Usage Restrictions All rights reserved. Editorial use only with credit. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.