Nuclear bomb test reveal brain regeneration in humans

[SMM]

Published by New Scientist, studies into adult hippocampal neurogenesis:

Nuclear bomb test reveal brain regeneration in humans

This stood out to me:

But the newborn brain cells in humans do not appear to live long. In rodents, the hippocampus gradually gets bigger as new cells are added. "In mice, there is a net increase," says Thuret. But this is not seen in humans – in fact, our hippocampus slowly shrinks. "There are more dying than being born," she says. The reason for this turnover remains unknown.

Many studies in mice show that young neurons are necessary for forming new memories. But this has not been tested in humans.

There is also this Feel Guide's article which can be found here.
In one part it states:

“In effect, a small population of our brain cells remains permanently young, renewing itself continually.”

 

[MoonGlow]

I ought to point out that this article isn't claiming radiation causes brain regeneration, just that people who have been exposed have been used to study regeneration.

 

[SMM]

I had the idea that it claimed that radiation impairs regeneration, though mainly effects only certain cells..?

 

[MoonGlow]

It's somewhat misleading, though I don't believe this was intentional. If you read closely, you see that the people in above-ground tests absorbed a higher-than-usual dose of c-14, which made its way through the food chain to settle in their growing brains. By comparing the cells that developed during that period to cells that have developed subsequently, we can tell that there was new growth, and figure out exactly how much there is. This new growth has long been speculated to be going on in all people, but without radiocarbon tracers, the direct evidence has been lacking.