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| Science & Technology |
| Adult Neurogenesis – A Pointed Review |
| 2018-04-08 |
| h/t Instapundit We had this article a few days ago about neuron growth in adults. Turns out there dozens of publications with thousands of citations - and it's all b*llshit [SlateStarCodex] Gage’s Neurogenesis In The Adult Brain, published in the Journal Of Neuroscience and cited 834 times, begins: A milestone is marked in our understanding of the brain with the recent acceptance, contrary to early dogma, that the adult nervous system can generate new neurons. One could wonder how this dogma originally came about, particularly because all organisms have some cells that continue to divide, adding to the size of the organism and repairing damage. All mammals have replicating cells in many organs and in some cases, notably the blood, skin, and gut, stem cells have been shown to exist throughout life, contributing to rapid cell replacement. Furthermore, insects, fish, and amphibia can replicate neural cells throughout life. An exception to this rule of self-repair and continued growth was thought to be the mammalian brain and spinal cord. In fact, because we knew that microglia, astrocytes, and oligodendrocytes all normally divide in the adult and respond to injury by dividing, it was only neurons that were considered to be refractory to replication. Now we know that this long accepted limitation is not completely true Subsequent investigation has found adult neurogenesis in all sorts of brain regions. Wikipedia notes that "In humans, new neurons are continually born throughout adulthood in two regions of the brain: the subgranular zone and the striatum", but adds that "some authors (particularly Elizabeth Gould) have suggested that adult neurogenesis may also occur in regions within the brain not generally associated with neurogenesis including the neocortex", and there’s also some research pointing to the cerebellum. Some research has looked at the exact mechanism by which neurogenesis takes place; for example, in a paper in Nature cited 1581 times, Song et al determine that astroglia have an important role in promoting neurogenesis from FGF-2-dependent stem cells. Other research has tried to determine the rate; for example, Cameron et al (1609 citations) find that there is "a substantial pool of immature granule neurons" that may generate as many as 250,000 new cells per month. Still other research looks at the chemical regulators ‐ a study by Lie et al, cited 1312 times, finds that Wnt3 signaling is involved. (which is making you more nervous ‐ the fact that I keep emphasizing how many citations these studies have, or the fact that one of the principal investigators is named "Lie"?) But the most exciting research has been the work identifying the many important roles that neurogenesis plays in the adult brain ‐ roles vital in understanding learning, memory, and disease. ...Fun fact: there’s no such thing as adult neurogenesis in humans. At least, this is the conclusion of Sorrells et al, who have a new and impressive study in Nature. They look at "59 post-mortem and post-operative slices of the human hippocampus" and find "that recruitment of young neurons to the primate hippocampus decreases rapidly during the first years of life, and that neurogenesis in the dentate gyrus does not continue, or is extremely rare, in adult humans." Also, the subgranular zone, the supposed part of the brain where neurogenesis begins, isn’t even a real structure. And you expect Truth from politicians, or journalists, or social "scientists"! I thought about tagging it under "Home Front: Culture Wars" |
| Posted by:g(r)omgoru |
| #4 Me too, Skid. Last year I learned a new word: co-morbidity, when more than one thing wants to kill you. Ailments that is, not people this time. |
| Posted by: brujotejano 2018-04-08 16:13 |
| #3 I know mine is. |
| Posted by: Skidmark 2018-04-08 14:00 |
| #2 And who knows — the horse may yet learn to sing. IMO, the system is rotten to the core. |
| Posted by: g(r)omgoru 2018-04-08 13:32 |
| #1 With the aging of the global population, there is desperation around the idea that senility can be prevented or reversed. Still, better to know the truth as it currently is. Thank you, g(r)omgoru. And who knows — the horse may yet learn to sing. |
| Posted by: trailing wife 2018-04-08 12:45 |