Yes, I Am Now Convinced The Brain Ages In Stages

 

                Tracking how brain connections change using MRT imagery

The notion that our brains age in distinct stages is one I have seriously considered, especially over the past quarter century as I've found my own mental agility and processing rate diminish. (Of course, a lot of the recent decline can be attributed to having to start androgen deprivation therapy to try to contain metastatic prostate cancer.)  But even before commencing ADT with Firmagon I have noted brain changes over decades  - especially in the time since graduating with my M.Phil. in Physics. To wit, my most recent attendance at a scientific conference last year:

Looking Back On Last Week's Solar Dynamics Workshop - One Of The Best Meetings I've Ever Attended

Showed me clearly that the time for delivering scientific papers, far less attending conferences, is basically over. It was all I could do to basically keep up and absorb the material and research presented in the SDO 2025 workshop. (And there was no way in hell I was staying for the final day's Python coding workshop!)

But how and why do these distinct brain 'ages' occur and is there any evidence for them? It turns out there is, now finally,  as neuroscientists have been able to use advanced imagery to track brain connections, development. (See top graphic).  Basically, this research has shown different ages at which the connections in our brains shift. The average ages turn out to be: 9, 32, 66 and 83, Well I am now 13 years past 66 and only 3 1/2 to 83 - and it shows. (Including in the much longer time to write a blog post)

According to a December, 2025 WSJ article, ('Your Brain Changes In Distinct Stages Research Shows): 

 "The adolescence phase lasts until age 32. The brain then enters a period of stability until early aging begins at age 66."

I can vouch for this as when I hit 66 was when I first confronted my mortality after being given a prostate cancer diagnosis,

Verdict Is: Prostate CANCER......So Now What?

And basically, for all intents, things haven't been the same since. This is given each succeeding year has resulted in more tests, more treatments, and sped up aging especially after the radiation in Sept., 2012. Add in the effects of the ADT and I feel I aged 25 years in the actually elapsed 13. (And each forthcoming PSA test is looked on with dread.)

But let's bear in mind the WSJ report is based healthy aging for brains, and first published in November, 2025 in the journal, Nature Communications. We find therein that the study researchers examined results from about 4,000 brain scans taken from people in the U.S. and UK.  These scans ranged from those of a newborn baby to a nonagenarian.

They basically showed how white matter -  a fatty substance insulating nerve fibers connecting different brain regions - enabled the researchers to see the changing connections over time. (Using an MRI).  Such mapping also enabled them to create an "average brain" for each year of life.  Machine learning then helped to pinpoint phases of significant change defined by the data.

For example, during the period from birth to age 9, the brain undergoes massive pruning of connections which aren't used - given the amount of excess wiring we're born with. But during the period from age 9 to 32  the brain does more with less wiring, hence becoming more efficient.

When does the brain finally become 'mature'?  Likely when it becomes most efficient in terms of the wiring, at age 32.  There is then the blessed period of 'consistency' and 'stability' (age 32 to 66) as opposed to endless emotional upheavals, convulsions and petty neuroses. (75% of mental health conditions begin in the early 20s we are informed).  This period between ages 32-66 also aligns with a plateau in our intelligence.

But the bad news begins at just past 65 when brain shrinkage occurs - increasing year by year.  This diminishes the integrity of white matter and also begins the decline in cognitive function. Past the age of 83 the brain must "rely on a small  number of highly used interregional pathways."

Bottom line: If you want to keep that brain functioning then once you're past 66 you better use it - or risk losing it. Forget the Tik Tok and other smart phone obsession - stick to chess and reading adult books, like Jean-Paul Sartre's Being and Nothingness - or at least Stephen Hawking's 'A Brief History of Time'.

See Also:

Topological turning points across the human lifespan | Nature Communications