[cdcox]

The original study https://www.nature.com/articles/nature25975 that prompted the SSC article has an interesting discussion of this result in their supplement:

"A study using 14C birthdating on sorted NeuN+ nuclei suggested that hundreds of new neurons are generated per day in the adult human hippocampus, with little decline with age. The results obtained from this method differ from the data presented here and other histology studies that show a sharp decline in markers of newly formed neurons during early postnatal development. Birthdating with 14C relies on the isolation of neuronal nuclei using NeuN antibodies, but subpopulations of oligodendrocytes and microglia can also express NeuN. 14C could also possibly become incorporated into DNA through methylation or DNA repair independent of cell division, processes that have been shown to occur at higher rates in the hippocampus. The proposed addition of new neurons to the adult caudate nucleus using this method is not supported by other work in the human or BrdU labeling in adult macaques. The 14C method is an innovative approach to perform birthdating in postmortem human samples, but it has not been validated in animal studies."