A new atlas tracks brain changes from childhood to age 97. Most cell populations in the prefrontal cortex settle into relative stability around 24, then molecular activity rises again in later life.
Researchers found the shift in the dorsolateral prefrontal cortex, a region involved in planning, problem-solving, reasoning, working memory and decision-making. The change appears around age 24. Molecular activity rises again in later life, especially in cells that support and protect neurons.
The study was published in Nature on September 23. It analysed 1,307,674 cellular nuclei profiles from 284 donors aged from childhood to 97. The atlas tracks gene expression across the lifespan and shows how neuronal and glial populations behave inside one important part of the cortex.
Mount Sinai describes the work as the first population-scale single-cell transcriptomic atlas of the dorsolateral prefrontal cortex across the human lifespan.
The 284 donors were described in the study’s supporting accounts as neurotypical, allowing the atlas to focus on age-related molecular patterns rather than diagnosed brain disorders.
The strongest changes do not continue at the same pace throughout life. Most neuronal and glial subtypes undergo major remodelling during early development. Their patterns reach relative stability around age 24.
That stability is real but incomplete.
Some cell populations keep changing with age. They include inhibitory neurons that express somatostatin and oligodendrocyte precursor cells. This separates the broad pattern of stability from the specific groups that remain biologically active beyond early adulthood.
The dorsolateral prefrontal cortex is also involved in working memory and decision-making, not only in planning and reasoning. That makes its age-linked molecular map relevant to several higher cognitive functions, while still limiting the conclusions to this particular cortical region.
The data show three broad phases. Early development brings strong remodelling. Adult life brings relative stability. Old age brings renewed molecular activity.
During the first phase, neurons change their connections as brain circuits form and reorganise. After age 60, several glial populations show stronger changes. They include astrocytes, microglia and oligodendrocytes.
The research materials also describe renewed remodelling after age 65. These age markers describe different parts of the same later-life shift.
Cellular stress and immune responses are linked to the later changes. The atlas also records weaker synchronisation in some neuronal circadian genetic rhythms during old age. Ageing affects neurons and the support cells around them.
Juan Lerma, a CSIC researcher who contributed to the assessment circulated by Science Media Centre Spain, said the atlas makes it possible to identify changes in cellular composition. He also said it can help researchers examine possible periods of resilience and vulnerability during development. Marta Nieto likewise stressed the value of studying the cells that support and protect neurons when analysing brain ageing.
Reuters separately described about age 24 as a transition point after which most cell types in this region become more stable. Nature's press material also says that midlife stability begins around 24, with slower changes in cell composition afterward.
The study has a clear limit. It examines molecular patterns in the dorsolateral prefrontal cortex using tissue from donors. It does not show that every part of every person's brain finishes maturing at exactly 24.
That limit matters.
The age identified by the atlas is a turning point in the measured cellular patterns. It is not a universal biological deadline. The findings apply to one cortical region, not to the whole brain.
The atlas does not give one age at which the entire brain becomes complete. It maps the balance between early development, adult stability and later molecular activity across different cell types.
By covering the period from childhood through advanced age, the work gives scientists a reference for studying development and ageing. It may also help them separate normal age-related change from possible changes linked to neurological and psychiatric disorders.
The evidence supports a more precise view of brain maturity. Broad stability appears around 24 in this region. Selected cell populations keep changing. Ageing later reactivates molecular processes.
The finding does not mean that the brain suddenly finishes at 24. It also does not mean development continues at the same pace forever. The atlas shows a shift from intense early remodelling to adult stability, followed by renewed activity later in life.
