New study claims .... Adolescence - from nine to 32

 These are five brain phases:

Childhood - from birth to age nine

Adolescence - from nine to 32

Adulthood - from 32 to 66

Early ageing - from 66 to 83

Late ageing - from 83 onwards

"The brain rewires across the lifespan. It's always strengthening and weakening connections and it's not one steady pattern - there are fluctuations and phases of brain rewiring," Dr Alexa Mousley told the BBC.

These patterns have only now been revealed due to the quantity of brain scans available in the study, which was published in the journal Nature Communications. 

During Childhood; 

the brain gets less efficient during this stage. It works like a child meandering around a park, going wherever takes their fancy, rather than heading straight from A to B.  

Adolescence starts 

... around the onset of puberty, but this is the latest evidence suggesting it ends much later than we assumed. 

It was once thought to be confined to the teenage years, before neuroscience suggested it continued into your 20s and now early 30s.

This phase is the brain's only period when its network of neurons gets more efficient. 

** The brain stays in the same phase between nine and 32.

Early ageing - This kicks in at 66, but it is not an abrupt and sudden decline. Instead there are shifts in the patterns of connections in the brain.

Instead of coordinating as one whole brain, the organ becomes increasingly separated into regions that work tightly together - like band members starting their own solo projects.

Although the study looked at healthy brains, this is also the age at which dementia and high blood pressure, which affects brain health, are starting to show.

Late ageing - Then, at the age of 83, we enter the final stage. 

There is less data than for the other groups as finding healthy brains to scan was more challenging. The brain changes are similar to early ageing, but even more pronounced.  

Prof Tara Spires-Jones, director of the centre for discovery brain sciences at the University of Edinburgh, said: "This is a very cool study highlighting how much our brains change over our lifetimes."

She said the results "fit well" with our understanding of brain ageing, but cautioned "not everyone will experience these network changes at exactly the same ages".