© THOMAS DEERINCK, NCMIR/SCIENCE SOURCE
NO NEW NERVE CELLS A preliminary study suggests that new nerve cells are not produced in adult humans’ hippocampi, results that conflict with earlier data. Hippocampal nerve cell axons are shown in blue, and glial cells are green. All cells’ nuclei are stained red.
In stark contrast to earlier findings,
adults do not produce new nerve cells in a brain area important to memory and navigation, scientists conclude after scrutinizing 54 human brains spanning the age spectrum.
The finding is preliminary. But if confirmed,
it would overturn the widely accepted and potentially powerful idea that in people, the memory-related hippocampus constantly churns out new neurons in adulthood. Adult brains showed no signs of such turnover in that region, researchers reported November 13 at a meeting of the Society for Neuroscience in Washington, D.C.
Previous studies in animals have hinted that
boosting the birthrate of new neurons, a process called neurogenesis, in the hippocampus might enhance memory or learning abilities, combat depression and even stave off the mental decline that comes with dementia and old age (
SN: 9/27/08, p. 5). In rodents, exercise, enriched environments and other tweaks can boost hippocampal neurogenesis - and more excitingly, memory performance. But the new study may temper those ambitions, at least for people.
Comment: You can read more about the spike in radioactivity over Europe in September and October here. Bear in mind that the same thing happened already in January and February, except that back then the source was suspected to be somewhere near the Arctic Circle.