Science imgae (IMAGE) Salk Institute Caption The brain is comprised of lipids or fats, but the role of these molecules in health and disease remains unknown. The newly identified class of lipids, called SGDGs, decrease with aging, which suggests they may play a role in brain aging. Credit Salk Institute Usage Restrictions with credit and related coverage. License Original content 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.