The brain expands and shrinks over time | Hacker News Reader

The brain expands and shrinks over time

nature.com

114 pointsmakaimc46 comments

According to the chart, the only thing that increases in late adulthood is ventricular volume. Interesting.

"An increase in ventricle size is associated with degenerative brain disease and gait."

https://www.mayoclinic.org/medical-professionals/neurology-n...

Nice. Hopefully this puts to rest "your brain gets better as it ages" nonsense. There has to be a correlation between the physical changes of the brain as we age and the decline in cognition.

Edit: The researchers website with real time charts, male/female data/breakdown, etc

https://brainchart.shinyapps.io/brainchart/

Sorry, who thinks your brain gets better as it ages and why would anyone think that?

Maybe people whose brain is getting worse so they can't think straight?

What if it's getting better because it's fitting reality more tightly by cutting off slack neurons? :)

According to the chart there, your largest gray matter volume is at 6 and greatest cortical thickness is between 1 and 6. I'll leave it to you to decide whether your brain is better now than at 6. (Assuming you're reading this while being significantly older than 6.)

"Well ya see, Norm, it’s like this… A herd of buffalo can only move as fast as the slowest buffalo. And when the herd is hunted, it is the slowest and weakest ones at the back that are killed first. This natural selection is good for the herd as a whole, because the general speed and health of the whole group keeps improving by the regular killing of the weakest members. In much the same way, the human brain can only operate as fast as the slowest brain cells. Excessive intake of alcohol, as we know, kills brain cells. But naturally it attacks the slowest and weakest brain cells first. In this way, regular consumption of beer eliminates the weaker brain cells, making the brain a faster and more efficient machine. That’s why you always feel smarter after a few beers.”

-Cliff Clavin

You compare an effect of a randomly applied poison to one done by the brain itself acting specifically (the early age pruning).

https://en.wikipedia.org/wiki/Synaptic_pruning

In any case, I see no differentiation in the previous comments between the cells, types of cells - neurons being only one type in the brain - and connections. Axons of neurons are quite substantial and are a large part of the brain mass, it isn't only about neurons at all.

Glial cells are not only just "support" either. Example: https://www.simonsfoundation.org/2019/07/29/frustrated-fish-... -- or https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2894949/

It’s a quote from the beer drinking postal worker character of the 70’s American TV Show “Cheers”…

Our president is 79 and many members of our congress are over 80 years old

When reasoning, you have to lay out all the assumptions. Not even ceteris paribus they would be better at 40, before many further decades of cultivation and experience.

Who thinks members of congress are smart?

What if they are smart and they're getting exactly what they want? Look at Paul Ryan who accomplished all he set out to do so he retired to a sinecure post at Fox News that pays millions. I'd hardly call him a fool.

Not physically, but the informational content and structure. Supposedly you get wiser and expert.

And in fact, this «putting to rest» thing is nonsense, unless somebody really believed that the brain gets younger with age. The real point is about how heavily or how little degeneration impacts proficiency.

> Supposedly you get wiser and expert.

Well, you do. I'm over the hill and I'm objectively more capable than I was in my 20s. It's possible for this to be true despite declining cognition.

My abilities differ. In my 20s I relied on sheer problem solving ability. I could focus for days on a problem. I think I could better visualize specifics and more reliably remember.

Wisdom is different. Later in life I find I'm more able to navigate deeper social issues, more capable of seeing bigger picture patterns. I manage myself better, and these higher order changes result in my getting a lot more done than when I was younger.

There's much more to real world brain performance than certain narrow measures of technical capability.

I think there's a loss of basic stimulation while a finer perception of abstraction. This low stimulation state increase degradation at unhealthy rates.

I assume people doing subtle physical and mental activities (danse, music, craft) can maintain both.

Absolutely subjective layman opinion here, but regardless of what decay the brain may experience, I think it's likely that experience provides a huge counterbalance to it, as you can solve problems faster than before because you have already experienced them, or can relate them to something else.

Who said brain size has anything to do with performance?

At least it works with microprocessors, at least if to measure a microprocessor's size in transistors.

Seidlitz has amassed more than 120,000 brain scans — the largest collection of its kind — to create the first comprehensive growth charts for brain development.

The unusually large sample size alone makes this an important body of work.

Age will eventually catch up, but meditation, aerobic exercise, good sleeping pattern, certain video games, good tangible social connections, exploring novel things are shown to moderate the decline. While stress/tension, sedentary lifestyle and most importantly loneliness accelerate the decline.

Loneliness? Source for that?

Here is an article that references several studies but a search including 'loneliness and health' will bring up dozens of studies.

https://www.brainandlife.org/articles/how-loneliness-affects...

What video games do you think are helpful? Any source for that?

Training with the n-back task (a memory game) has been shown in some studies to improve performance in other cognitive tasks.

https://en.wikipedia.org/wiki/N-back#Treatment

You missed the most important one... Diet!

I take Choline to help me remember.

What is choline?

I can’t remember

neurotransmitter precursor

I mean good for you, just remember that throughout history supplements have more often seemed to have caused more problems than otherwise. Including the fact that most large scale studies show people taking vitamins dying faster than otherwise.

Also how are you absolutely sure cholines making you remember better?

Totally agree with your point on taking supplements can shorten lifespans, in tablet form other ingredients are not that healthy, some chemicals that can be classed as a vitamin or mineral shouldnt be included and a-once-a-day delivery regime isnt always good for you either although its convenient.

Choline is used in the cell wall membrane, its also used in the connections between neurons and it also helps lower the pressure of the fluid in the alveoli to make the gas exchange better. So brain fog, seen with Covid, pregnancy (baby brain), and old age all sign of needing choline which can be reversed if taking amounts throughout the day. Thats the science I've read, its already there but even negative scientific studies highlight the minimum or maximum range of an amount a chemical for a pathway.

Its massively complex and I dont seen many entities except perhaps some massive drug companies who have developed drugs or practices giving away their knowledge by virtue of product or action.

Agreed. Finding the right context with the right amount of benefitial "stressors" can surely alter the evolution. Just like chinese crowd doing taichi can do more acrobatics at 80 than I can do at 40.

I seem to recall a number of "$X is bad for you because it shrinks the brain" articles. Wonder how many will be reviewed and find that $X is still bad for you despite whatever effect they alleged being even less likely to be meaningful.

that's the bitch about "bespoke science," you can report that "the Science says" whatever you like (if you can afford it) but then it requires maintenance to make sure it keeps saying that.

This is a very impressive data set. I'm curious about the statistical techniques the scientists used to normalize the measurements across different imaging machines. Worth digging into for the stats-inclined.

Do these graphs help confirm that "over the hill" age is around 40?

In the chart, all the metrics look like they are in a state of decline in your mid 30s. So we can safely assume by 40, you ( or your brain specifically ) is over the hill.

We can't safely assume that universally due to selection effects the data for these kinds of studies has.

Yeah, just to point out something specific: only 1% of the dataset comes from Asia. Something similar might happen in other dimension. We don’t know if 50% of the images come from people with genetic degenerative brain disease or not. MRI is special enough that it would be hard to say the sampling is similar to the general population

I don't think it is "over the hill" capabilities wise to some extent.

What does "over the hill" mean? That there's a snowball in cognitive decline after 40?

I think that’s the age when most workers start moving into positions where they no longer need to actively solve hard, abstract problems, and the brain starts to atrophy just like a muscle that gets no exercise.

Combine that with an increase in stress levels due to no longer being able to directly ensure the success of work and you get a managerial brain grinder.

It's interesting how many folks seem kinda obsessed with brain size...

Does anyone know of a company (or university, govt. agency, etc.) which hired or promoted on the basis of "physically larger brains perform better" - and was actually successful with that? Probably using some rough cranial measurements as a proxy for brain size, vs. MRI's.

I'd bet that the real-world performance of that strategy would be considerably worse than random chance, due to various knock-on effects.

Phrenology has had its adherents over the years, none that I know of were successful in proving any real predictive power though.

Brain size and intelligence seem to only be correlated in the loosest of ways anyway. Everything we know about performance of information processing systems says that their size and weight is almost irrelevant compared with their design. We expect simple algorithmic optimizations to provide orders of magnitude of improvement, and more advanced ones to provide more orders of magnitude on top of that.

If I recall rightly the metric with the best performance is ratio of brain to body mass. This would make sense if you assume that brain performance is determined largely by its 'design' and scales only modestly with mass, and that creatures of the same species share the same design.

It's been proven that brain size has close to nothing to do with intelligence. Hell, some people get half of their brains removed to stop intractable seizures and if it happens as a child they tend to recover completely and live normal lives

In other words all the ”X shrinks your brain” scare stories are just that, scare stories.

i think i'm in a small brain period right now

If anyone is interested in the pdf: https://oa.mg/work/10.1101/2021.06.08.447489

I thought MRI had no absolute spatial scale unlike a CT or X-ray does when a known dimension radio-opaque reference marker object is put into the field of view. Am I mistaken here?

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