The brain's five eras

Scientists map phases of neural wiring — from childhood leaps to 80s — shaped by key turning points

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The human brain goes through five major eras of structural changes over a lifetime — marked by turning points at ages nine, 32, 66 and 83 — as it rewires to support varied ways of thinking as one grows, matures and ultimately declines, a study has suggested.

Age nine is when communications between brain networks developed since birth transition to the adolescent phase, which then lasts up to age 32, researchers led by those from the UK's University of Cambridge explain.

Early thirties is when the brain's neural wiring shifts into "adult mode" — the longest era lasting over three decades and marked by a stabilising of the brain's architecture. Age 32 is also the "strongest topological turning point" of the entire lifetime, they said.

Age 66 was found to signal the start of an "early ageing", and age 83 that of a "late ageing" stage of brain structure.

The findings published in the journal Nature Communications "help us understand why some brains develop differently at key points in life, whether it be learning difficulties in childhood, or dementia in our later years," lead researcher Alexa Mousley, a graduate student at the University of Cambridge's cognition and brain sciences unit, said.