A comparison of stained neural progenitors (pink) in a young (left) and old (right) brainCOURTESY OF MAURA BOLDRINIAdult human hippocampi are home to thousands of immature neurons, researchers report today (April 5) in Cell Stem Cell. The result runs counter to a paper published last month in Nature that found no evidence of neural precursor cells or immature neurons in adults. Such contradictory findings raise questions about researchers’ understanding of neurogenesis in human adult hippocampi, which are central to learning and memory.
“There’s been a long-standing debate about adult human neurogenesis,” Xinyu Zhao, a neurobiologist at the University of Wisconsin-Madison who was not involved in either study, tells The Scientist. She says the latest work in Cell Stem Cell is notable because it uses stereology—the gold standard of neurogenesis studies in animals—to count immature and mature neurons in the hippocampi of healthy humans. Stereology can determine the number of individual cell types in tissue, even when the sample has been sliced into sections.
“I have never seen anybody do this in human tissue because availability of human tissue is a major problem,” Zhao says. “The fact they did this counting on the whole hippocampal tissue is remarkable.”
We dispute the interpretation of their cellular staining experiments as ...
