Frisén Team Confirms New Neurons in Adult Hippocampus Up to Age 78
Updated
Updated · spacedaily.com · Jun 29
Frisén Team Confirms New Neurons in Adult Hippocampus Up to Age 78
1 articles · Updated · spacedaily.com · Jun 29
Summary
Post-mortem tissue from 35 people — from newborns to age 78 — showed dividing progenitor cells and immature neurons in the adult hippocampus, giving the strongest direct evidence yet of ongoing neurogenesis.
Single-nucleus RNA sequencing and cell-mapping methods let Jonas Frisén's Karolinska team trace the full lineage from quiescent stem cells to dividing precursors to immature neurons — the missing link that had kept the debate open.
The finding is limited to the dentate gyrus of the hippocampus, not the whole brain, and adults varied sharply: some had many progenitor cells, others almost none.
The result strengthens earlier pro-neurogenesis studies from 1998 and 2013 against a 2018 paper that found adult neuron formation undetectable, while leaving open how many functional neurons are ultimately added and whether other groups can reproduce it.
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Overview
For many years, scientists believed that humans could not grow new neurons after birth. This idea was challenged when researchers used advanced techniques to observe new neuron growth in rodents, especially in the hippocampus, which is important for memory and learning. These rodent findings encouraged scientists to look for similar evidence in humans, but technical difficulties—like differences between rodent and human brain markers and the low number of new cells—led to inconsistent results. Over time, improved methods and direct observations finally confirmed that adult humans do generate new neurons, settling a long-standing debate and opening new possibilities for brain health research.