BOB HIRSHON (host):
Crowd control in the fetal brain. I’m Bob Hirshon and this is Science Update.
Killing healthy brain cells may be an important part of prenatal development. This according to neuroscientist Stephen Noctor of the University of California, Davis. He and his colleagues studied microglial cells, which eat up dead or defective brain cells. Looking at fetal brain tissue from monkeys and rats, Noctor’s team found microglial cells mixed with clusters of stem cells, which had been rapidly dividing. Surprisingly, though, the researchers found nothing wrong with the stem cells.
STEPHEN NOCTOR (University of California, Davis):
There’s a caveat to everything, it could be that there’s some signal that we haven’t found yet, but the evidence we’ve gathered suggests that the microglia are targeting healthy neural stem cells.
It’s not clear why, but Noctor suspects the microglial cells help limit the number of neurons in the brain. That may sound strange, but there’s growing evidence that when it comes to brain development, too much can be counterproductive. I’m Bob Hirshon for AAAS, the Science Society.