Brain enters new biological phase between ages 50 and 75, study finds

A study published in Science reveals that the human brain undergoes a significant transformation between ages 50 and 75, particularly in the hippocampus, a region vital for memory and learning. Researchers from the New York Genome Center found that microglia—the brain's immune cells—decline dramatically during this period and are replaced by cells with stronger inflammatory signals, challenging the long-held belief that these cells persist throughout life Source: infobae, clarin.

Key findings

• Microglia formed during embryonic development decrease sharply between 50 and 75, replaced by cells resembling blood-derived immune cells with elevated inflammatory markers Source: infobae, clarin.
• The study analyzed post-mortem brain tissue from 40 adults aged 20 to 95 without known neurological diseases Source: infobae.
• The research also found that the genome's architecture erodes with age, suggesting that loss of genome organization is a fundamental feature of brain aging Source: clarin.

Implications

Lead author Bing Ren emphasized that microglia are "fundamental for maintaining brain homeostasis," and when they fail, toxic materials accumulate, potentially triggering inflammation linked to neurodegenerative diseases Source: clarin. Co-author Xiangmin Xu noted that aging is not a gradual decline but involves coordinated remodeling of immune, vascular, and neuronal systems Source: clarin. This discovery could help explain why aging increases the risk of cognitive decline and conditions like Alzheimer's disease.