> But there is no neurogenesis of human dopaminergic neurons in the adult substantia nigra.
Two regions of the mature mammalian brain generate new neurons: (a) the border of the lateral ventricles of the brain (subventricular zone) and (b) the subgranular zone (SGZ) of the dentate gyrus of the hippocampus. [0]
In adult humans, neural progenitors migrate from the early postnatal SVZ into neocortical and striatal areas [1].
Indeed, as I wrote elsewhere. (I can't directly respond to your other comment, with which I also agree).
But there are two relevant questions: first, does this constitute orthotopic neurogenesis in any meaningful way? The progenitors are specified as interneurons in both the olfactory bulb or the dentate gyrus, certainly in the absence of any factors that encourage transition to a dopaminergic phenotype. Second, is there enough neurogenesis in the adult human brain for any purpose? Probably the most careful scientist in this space is Arturo Alvarez-Buylla, and his two Nature papers on postnatal neurogenesis in humans [0, 1] paint a fairly bleak picture.
> his two Nature papers on postnatal neurogenesis in humans [0, 1] paint a fairly bleak picture.
Science is neither bleak nor joyous. Science is just a process for uncovering facts, which may or may not hint at mechanisms that may or may not yield future possibilities.
The future is not writ yet.
Exercise-Mediated Neurogenesis in the Hippocampus via BDNF
Two regions of the mature mammalian brain generate new neurons: (a) the border of the lateral ventricles of the brain (subventricular zone) and (b) the subgranular zone (SGZ) of the dentate gyrus of the hippocampus. [0]
In adult humans, neural progenitors migrate from the early postnatal SVZ into neocortical and striatal areas [1].
[0] https://pubmed.ncbi.nlm.nih.gov/31568602/
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4564523/
see also
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3106107/
https://translationalneurodegeneration.biomedcentral.com/art...