New brain cells!

[Sara S]

From delancyplace.com


In today's excerpt-the brain can grow new
neurons, but these disappear unless
cognitively challenged:



"Fresh neurons arise in the brain every day.
... Recent
work, albeit mostly in rats, indicates that
learning enhances the survival of new neurons
in the
adult brain, and the more engaging and
challenging the problem, the greater the
number of
neurons that stick around. These neurons are
then presumably available to aid in situations
that tax the mind. It seems, then, that a mental
workout can buff up the brain, much as
physical exercise builds up the body. ...



"In the 1990s scientists rocked the field of
neurobiology with the startling news that the
mature
mammalian brain is capable of sprouting new
neurons. Biologists had long believed that this
talent for neurogenesis was reserved for young,
developing minds and was lost with age. But in
the early part of the decade Elizabeth Gould,
then at the Rockefeller University,
demonstrated that new cells arise in the
adult brain--particularly in a region called
the hippocampus,
which is involved in learning and memory.
...



"Studies indicate that in rats, between 5,000
and 10,000 new
neurons arise in the hippocampus every day.
(Although the human hippocampus also welcomes
new neurons, we do not know how many.) The
cells are not generated like clockwork,
however. Instead their production can be
influenced by a number of different environmental
factors. For example, alcohol consumption has
been shown to retard the generation of new
brain cells. And their birth rate can be enhanced
by exercise. Rats and mice that log time on a
running wheel can kick out twice as many new
cells as mice that lead a more sedentary
life. ...



"Exercise and other actions may help produce
extra brain cells. But those new recruits do not
necessarily stick around. Many if not most of
them disappear within just a few weeks of
arising. Of course, most cells in the body do
not survive indefinitely. So the fact that
these cells die
is, in itself, not shocking. But their quick
demise
is a bit of a puzzler. Why would the brain go
through the trouble of producing new cells only
to have them disappear rapidly?




"From our work in rats, the answer seems to
be: they are made 'just in case.' If the
animals are cognitively challenged, the cells
will linger. If not, they will fade
away."



Tracey J. Shors, "Saving New Brain Cells,"
Scientific American, March 2009, pp.
47-48.

[Yubajeff]

Once again, in my usual contrarian manner, I cannot help but comment on the simplistic thinking of the "experts" in their fields. The attainment of wisdom and optimal brain development involves more "pruning" of neurons or to be more precise, an ideal ratio between quantity of neurons and the quantity and quality of synaptic connections. The number of brain neurons peaks out in early adolescence at something like 100 billion neurons, with maybe one trillion supporting neuroglial cells. Brains produce neurons at the astounding rate of 50,000 per SECOND during the pre-pubertal period!
So if mere quantity of neurons were important than the sages would all be 12 year olds. This proves "it ain't the meat, it's the motion" that counts. The implications for conditions like autism, ADD, and dementia are considerable, and I maintain that this "in the box" thinking explains the lack of progress by academia and the medical establishment in their research.

[Sara S]

I would have to read the entire article, but it seems to me that the major points of this excerpt are that, contrary to many years of accepted dogma, new research shows that the adult brain still produces lots of new neurons; and that there are physiological factors which can affect their longevity and usefulness.
I assume that they posit an acceptable ratio between those and their synaptic connections.
I don't see anything here which asserts that "mere quantity" of neurons are important.


One of my favorite birthday cards of all time says on the front:

"The human brain loses 50,000 cells every day!"

and inside: "Or is it 50 million? I forget."

Sara S.

Once again, in my usual contrarian manner, I cannot help but comment on the simplistic thinking of the "experts" in their fields. The attainment of wisdom and optimal brain development involves more "pruning" of neurons or to be more precise, an ideal ratio between quantity of neurons and the quantity and quality of synaptic connections. The number of brain neurons peaks out in early adolescence at something like 100 billion neurons, with maybe one trillion supporting neuroglial cells. Brains produce neurons at the astounding rate of 50,000 per SECOND during the pre-pubertal period!
So if mere quantity of neurons were important than the sages would all be 12 year olds. This proves "it ain't the meat, it's the motion" that counts. The implications for conditions like autism, ADD, and dementia are considerable, and I maintain that this "in the box" thinking explains the lack of progress by academia and the medical establishment in their research.

[Braggi]

... and I maintain that this "in the box" thinking explains the lack of progress by academia and the medical establishment in their research.

Uhhh, Jeff, we have no idea what you're complaining about.

Thanks for your contribution.

-Jeff