
Brain tissue samples suggest we stop growing new neurons in our early teens - merrier
http://www.latimes.com/science/sciencenow/la-sci-sn-new-neurons-age-20180307-story.html
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ramblerman
I see this as a positive. I always lamented the idea that as we grew older we
generated less and less neurons, and thus our learning capacity decreased (I
thought).

But it seems even young university students are no longer generating neurons.
Nor are the 30 year olds learning new languages or switching careers.

It seems neuron growth thus has nothing to do with 'plasticity' or our
capability to learn.

* disclaimer: I know very little of neurology so please correct any false assumptions.

~~~
heldrida
True! But someone who learns to play the guitar, or a language at 8 ~ 15 years
old shows skills that are very difficult to master (if not impossible) when
you are older. There's a lot of evidence of this if you talk with guitar
teachers, someone who moved and start speaking a different language when
adult, etc...

~~~
StavrosK
Can you point to any studies? I don't know if this is because our brains get
less plastic, or because we just stop bothering when we get older.

I have personally noticed some drop in language acquisition skills, but I'm
learning Spanish at 35 and I wouldn't say it's significantly harder than
learning English at 12 (apart from the fact that English is everywhere around
me all the time, but Spanish is very hard to come by).

~~~
heldrida
I've got Japanese friends who live in the UK for more than 10 years now, and
it's more Engrish then English, than anything else. My english sucks by the
way.

Maybe this will help you?

[http://www.jneurosci.org/content/36/3/755](http://www.jneurosci.org/content/36/3/755)

[http://pandora.cii.wwu.edu/vajda/ling201/test4materials/seco...](http://pandora.cii.wwu.edu/vajda/ling201/test4materials/secondlangacquisition.htm)

[https://www.sciencedaily.com/releases/2012/03/120328172212.h...](https://www.sciencedaily.com/releases/2012/03/120328172212.htm)

[https://www.sciencedirect.com/science/article/pii/S0093934X0...](https://www.sciencedirect.com/science/article/pii/S0093934X03000671)

[https://books.google.co.uk/books?id=5vvY2BDWZjEC&pg=PA251&dq...](https://books.google.co.uk/books?id=5vvY2BDWZjEC&pg=PA251&dq=Musical+Performance:+Expression+and+the+Development+of+Excellence&hl=en&sa=X&ved=0ahUKEwjqo4m2jN3ZAhVhLMAKHQ-
eBhEQ6AEILjAB#v=onepage&q=Musical%20Performance%3A%20Expression%20and%20the%20Development%20of%20Excellence&f=false)

[https://www.justinguitar.com/en/BC-101-CommonQuestions.php](https://www.justinguitar.com/en/BC-101-CommonQuestions.php)

~~~
StavrosK
Hmm, I don't see anything in there related to skill acquisition in younger vs
older people, I'm afraid. Most of the links are about skill acquisition in
general, and how the brain changes. One is to a Google book that won't show
the page (I don't know why, it says the page is unavailable), and the last
link is a teacher saying he guesses children learn more quickly because
they're more plastic (but I guess they learn faster because they have more
free time/willingness to practice)...

~~~
heldrida
Children are blank canvas, adults have habits; repetition makes it great but
it also perpetuates habits. To achieve mastery in some areas you'd have to be
born again.

Pinker's The Language Instict.

[https://en.m.wikipedia.org/wiki/The_Language_Instinct](https://en.m.wikipedia.org/wiki/The_Language_Instinct)

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2947444/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2947444/)

Noam Chomsky, the world's most popular linguistic
[https://study.com/academy/lesson/noam-chomsky-on-language-
th...](https://study.com/academy/lesson/noam-chomsky-on-language-theories-
lesson-quiz.html)

------
jmcgough
This article has some good insights from other researchers and their different
opinions on the study:

[https://www.theatlantic.com/science/archive/2018/03/do-
adult...](https://www.theatlantic.com/science/archive/2018/03/do-adult-brains-
make-new-neurons-a-contentious-new-study-says-no/555026/)

Adult neurogenesis in rats was my thesis focus, so it's interesting that all
the rat work we did may or may not translate over to humans.

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jey
I'm gonna wait for the replication, as always.

But what about all that exercise-induced BDNF-mediated neurogenesis stuff? Was
that only observed in mouse models?

~~~
SubiculumCode
Neurogenesis in the hippocampus and olfactory bulbs is ongoing trough the
lifespan. I am presuming this is not about that neurogenesis.

~~~
jey
Actually, that's exactly what they're claiming to refute:

> _A small number of papers had indicated that humans also possessed this
> capability, specifically in an interior region of the brain known as the
> hippocampus, which is associated with memory._

> _A team from UC San Francisco had hoped to see evidence of this neurogenesis
> in action._

> _Team members examined brain tissue samples collected from 59 human subjects
> who ranged in age from a 14-week-old fetus to a 77-year-old man. But they
> couldn 't find what they were looking for._

~~~
SubiculumCode
I am floored.

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kristiandupont
Absolute pitch is something that supposedly can only be learned before the age
of 6 but the drug Valproate seems to reopen this window.

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848041/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848041/)

~~~
rorykoehler
I learned it as a teenager and lost it in my 20s. Like anything I learned it
through practice and familiarity. Once I stopped working in music production I
slowly lost my absolute pitch too. Similar to the way I used to be able to
speak French but now can only string a few words together.

~~~
KozmoNau7
Similarly, I took German and French in school, and got quite good grades.
However, I've not had much occasion to use either language since then. I did
read some German news articles, so that part is sort of OK still.

I've been with my (German) girlfriend for about a year now, and have visited
her family in Germany a couple of times. It has really made me realize how
much of my ability to put together a sentence in German has simply vanished
over the last 15-16 years. I'm boning up using Duolingo now, because I really
want to be able to have a full conversation with her (not very English
speaking) family.

~~~
sergiosgc
I was having the same sort of difficulty with French. On vacation, I realized
my ability to speak fluently had vanished over a decade of non-use of the
language. I bought a few magazines, then a fiction book, and it's done
wonders.

It's much more interesting to read about something that I'm interested in than
it is to go through exercises. Since what you lose over time is mostly
vocabulary, reading is an efficient way to re-grok a language. You just have
to get over the initial bump, where you're reading really slow because you
stop frequently on unknown words.

~~~
KozmoNau7
My girlfriend has taken Danish classes for two years, and we try to speak as
much Danish as possible, with me giving her feedback on grammar and word
choices. In return she sends me news and other articles in German, where I try
my very best to read and understand them fully, without resorting to Google
translate. So far it's going pretty well, actually :-)

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bsder
I thought they used isotope analysis from nuclear testing fallout to prove
that the neurons in the brain are between 15-20 years old on average? How do
they reconcile this?

[http://www.physicscentral.com/explore/action/nuclear-
neurons...](http://www.physicscentral.com/explore/action/nuclear-neurons.cfm)

~~~
divbit
Afaik nature has good stuff, but it's not like a 'research journal' it's more
popular stuff. A quote from the article: "There are only a handful of studies
out there that have already attempted to look at this, and they came to wildly
different conclusions." So, although I didn't look into this more deeply, it
seems to me there is wide room to not take this popular article as 'full
confirmation'.

~~~
CuriouslyC
Nature is basically the most prestigious scientific journal, along side
Science. Getting a pub in either of those journals is considered a huge win.

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otakucode
This worries me. First, any study of neurology it must be kept in mind is done
on a specific population. The neurology of a Papua New Guinea highlander and
an upper middle class white kid from the suburbs of NYC are not going to have
the same brain development. Brain development does NOT proceed as a
consequence of aging. This is a dangerous and destructive myth that gets
perpetuated all the time. Brain development proceeds as a consequence of
experience. If you eliminate experience from a persons life, you will
eliminate brain development.

We can see this clearly in the very young. An infant must master binocular
vision by about 3 weeks old, or else they will never master it. Putting an
eyepatch on an infant because they are "not ready" for binocular vision or
because their brain "isn't mature" in the region responsible for that would
damage them for life. A child must be exposed to the general concepts of
language before about age 5 or else they will remain incapable of learning any
sort of language-based communication for their entire life. Likewise if you
were to restrict them and keep them away from language exposure because their
brains are 'not mature' or because they're 'not ready' for it or whatever, you
would do them grievous harm by actively preventing brain development.

There are similar critical periods and developmental milestones like the
Existential Crisis where children develop an understanding of death as the end
to life and understand their own mortality around age 10. It was always
thought that neuroplasticity pretty much disappeared after adolescence. I've
always wondered if that was a consequence of the way the life experience of a
person in a western society changes after adolescence. That is typically when
almost all experience of novelty comes to a grinding halt. Jobs are taken up,
spouses found, routines established. And without unique experience providing
intense stimulus to a brain, it will stop developing. Absent those stimuli, it
never would have developed in the first place. It is the origin of growth.

If we start to see neuroplasticity decreasing even earlier in members of our
society, I would not be terribly surprised given the degree to which
adolescence has been either criminalized or heavily regulated. And we will pay
the price for that.

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azinman2
Unless it happens somewhere other than the hippocampus..

~~~
chrisabrams
I was wondering as well, is it possible that there’s another part that it
happens instead?

~~~
jmcgough
Adult neurogenesis has been seen in other species in the olfactory bulb, I
don't think this has ever been observed in humans though.

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MarlonPro
Is this a blow to neuroplasticity?

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jateenjoshi
Not this result in itself. Neuroplasticity refers to the ability of existing
neurons of creating/pruning connections to other neurons.

However, separately, there is scientific evidence to show that neuroplasticity
decreases after adolescence.

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robbrown451
I appreciate the suggestion, but how am I supposed to do that?

~~~
taneq
And why would I listen to a brain tissue sample anyway?

