Prefrontal cortex aging

The prefrontal cortex (PFC), comprising Brodmann areas 9, 10, 11, 46, and 47 and related regions, is the cortical seat of executive function, working memory, cognitive flexibility, impulse control and prospective planning. It is among the latest brain regions to fully myelinate in adolescence and among the earliest to show measurable structural and functional decline with age: cortical thinning, dendritic retraction, reduced dendritic spine density and diminished dopaminergic and noradrenergic signalling accumulate from the fourth decade onward, even in the absence of overt pathology. Functional MRI studies show that older adults recruit PFC more bilaterally and diffusely than young adults performing equivalent tasks — a pattern interpreted as compensatory in some frameworks and as inefficiency in others. PFC age-related decline is accelerated by chronic stress (via glucocorticoid-mediated dendritic remodelling), hypertension and sleep disruption, and is modifiable through aerobic exercise, cognitively demanding activities and adequate sleep.