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Study questions whether adults can really make new neurons
Over the past 20 years, evidence that adult humans can produce hundreds of new neurons per day has fueled hope that ramping up cell birth could be therapeutic. Boosting neurogenesis, researchers speculate, might prevent or treat depression, Alzheimer's disease, and other brain disorders. But a controversial study in Nature this week threatens to dash such hopes by suggesting that the production of neurons declines sharply after early development and grinds to a halt by adulthood.
The results of the "exhaustive search" for new neurons in adult human and monkey brains "will disappoint many," says neuroscientist Paul Frankland of the Hospital for Sick Children in Toronto, Canada. "It raises concern that levels of neurogenesis are too low to be functionally important" in humans, adds another observer, René Hen, a neuroscientist at Columbia University. But he and others suggest that the study left much room for error. The way the tissue was handled, the deceased patients' psychiatric history, or whether they had brain inflammation could all explain why the researchers failed to confirm earlier, encouraging studies, Hen says.
Also at STAT News.
Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults (DOI: 10.1038/nature25975) (DX)
(Score: 0) by Anonymous Coward on Thursday March 08 2018, @05:59PM (7 children)
This paper is rocking the memory research world, FYI.
(Score: 2) by legont on Thursday March 08 2018, @07:20PM (6 children)
Care to comment on say London taxi drivers?
https://www.scientificamerican.com/article/london-taxi-memory/ [scientificamerican.com]
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 3, Insightful) by SubiculumHammer on Thursday March 08 2018, @07:55PM
Evidence for a relation between new neurons and volumetric change has always been tenuous, at best. There are a lot of thing things that contribute to the volume of a brain region. Most notably, from post-mortem cellular studies, volume differences seem to be due to two things: 1. Amount of water. 2. Degree and complexity of dendritic arborization.
(Score: 0) by Anonymous Coward on Thursday March 08 2018, @07:57PM
Different AC. The region can get larger on MRI without neurogenesis, it could just be more blood flow or increased density of the dendridtic/axonal arbors.
(Score: 3, Insightful) by tfried on Thursday March 08 2018, @08:04PM (3 children)
It's not clear that "brain growth" is the same as new neurons. From your own linked article:
Anyway, maybe I'm not really up-to-date, but I though the story went something like this:
Up until some 20 years ago, it was believed that no new neurons would grow in adults at all (and essentially not from age 2 or so up). Then came some studies that showed there was a very small but non-zero growth rate of new neurons after all. This raised hope - as the summary correctly states - that there is no hard barrier, and that the existent but marginal growth rate could be ramped up, pharmaceutically, somehow.
And so I don't really see how this new study changes anything in either direction.
(Score: 0, Troll) by realDonaldTrump on Thursday March 08 2018, @08:18PM
Science, so many times, it's nothing new. They do an experiment somebody already did. Big waste of time & money. VERY DUMB!
(Score: 2) by legont on Thursday March 08 2018, @11:11PM (1 child)
I was taught in school (many years ago) that adult brain does not get new neurons. They implied that one should train existing ones and not to destroy them (using alcohol or drugs). Some years later the evidence came up that brain actually grows while learning even in old age. They presumed it was because of new neurons. This study, it seems, supports the theory that number and complexity of axons - connections - is what matters. Perhaps only they grow?
Regardless, it looks to me like another "fat food makes you fat" bullshit moment. Why I am so harsh? Just imagine thousands of studies that came up with more neurons. Shall we repeal all those doctorates for falsification? Should we actually check those countless papers of established schools for fake and actually drag the cheaters out and, well, shame them?
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 0) by Anonymous Coward on Thursday March 08 2018, @11:40PM
Its not falsified (for the most part), just produced to really low standards. Eg, "the spot gets bigger on the mri when I do this, which could be due to reasons a:z. Reason a is my favorite so Ill assume thats true. Then to seem sciency Ill also rule out reasons b and c, but only hand wave reason d:f since I ran out of money."
Obviously, explanations g:z for the mri spot are left unaddressed at all and d:f will most likely be ignored going forward.