Scientists at Stanford University have uncovered a major clue to why the brain deteriorates with age. Their research points to breakdowns in the cell's protein production system, a process that appears to trigger widespread dysfunction linked to cognitive decline and neurodegenerative diseases such as Alzheimer's.

The study, published in Science, focused on how aging disrupts "proteostasis," or protein homeostasis. This system helps cells correctly build, maintain, and dispose of proteins. When proteostasis fails, damaged proteins can accumulate into harmful clumps that interfere with normal brain function.

Researchers say the findings provide one of the clearest explanations yet for why aging brains become increasingly vulnerable to disease and mental decline.

"We know that many processes become more dysfunctional with aging, but we really don't understand the fundamental molecular principles of why we age," said study author Judith Frydman, the Donald Kennedy Chair in the School of Humanities and Sciences at Stanford. "Our new study begins to provide a mechanistic explanation for a phenomenon widely seen during aging, which is increased aggregation and dysfunction in the processes that make proteins."