science π§ Brain aging isn't simple decay; it's a complex switch π€―
The traditional idea of steady brain tissue shrinkage is now outdated based on new studies. Researchers Zemke and colleagues found a midlife shift involving inflammation and energy issues in the hippocampus. This change is linked to the replacement of original microglia with highly inflammatory monocytes from the blood, starting in midlife. The blood-brain barrier is failing, allowing these peripheral immune cells to invade the brain. Some of these invading cells surprisingly show protective effects against Alzheimer's disease.