Researchers discover the source of new neurons in brain hippocampus

It was once believed that mammals were born with the entire supply of neurons they would have for a lifetime. However, over the past few decades, neuroscientists have found that at least two brain regions—the centers of the sense of smell and the hippocampus, the seat of learning and memory—grow new neurons throughout life. Researchers from the Perelman School of Medicine have shown that one type of stem cell that makes adult neurons is the source of this lifetime stock of new cells in the hippocampus.

Neurons in the dentate gyrus of the hippocampus
Neurons in the dentate gyrus of the hippocampus. Blue is the nuclei marker, green is the progeny of HOPX-expressing progenitor cells, and red is the marker of cell proliferation. (Image: Daniel A. Berg and Allison M. Bond/Penn Medicine News)

Published in Cell, these findings may help neuroscientists figure out how to maintain youthful conditions for learning and memory, and repair and regenerate parts of the brain after injury and aging.

“We’ve shown for the first time, in mammals, that neurons in the dentate gyrus of the hippocampus grow and develop from a single population of stem cells, over an entire lifespan,” says senior author Hongjun Song, a professor of neuroscience. “The new immature neurons are more flexible in making connections in the hippocampus compared to mature neurons, which is paramount for healthy learning, memory, and adjusting mood.”

“This process is unique in the brain,” says co-senior author and neuroscience professor Guo-li Ming. “In the hippocampus, these cells never stop replicating and contribute to the flexibility of the brain in mammals.

Read more at Penn Medicine News.