Even in Your 70s, Your Brain May Be Making New Memory Cells: Study Suggests - Video

In a new study published in the journal Science, Swedish researchers from the Karolinska Institutet have found compelling evidence that the human brain continues to produce new neurons in the hippocampus well into late adulthood. The study, which used advanced imaging and molecular techniques, adds weight to the idea that our brains remain more flexible and adaptable than previously believed, potentially paving the way for new therapies targeting memory loss and neurological diseases.

The hippocampus is a region of the brain known to play a crucial role in learning, memory, and emotion regulation. Until recently, scientists debated whether neurogenesis—the formation of new neurons—continued into adulthood. The new study by Professor Jonas Frisen and his team builds on earlier research from 2013 that demonstrated mature human brains are capable of generating new neurons in the hippocampus.

To investigate this phenomenon, researchers examined brain tissue from international biobanks, analyzing samples from individuals aged between 0 and 78 years. They utilized sophisticated tools such as flow cytometry to observe cell characteristics and single-nucleus RNA sequencing to monitor gene activity at the individual cell level. By incorporating machine learning, they were able to map the full trajectory of neuron development—from stem cells to immature neurons, many of which were still dividing.

The team also applied RNAscope and Xenium technologies, which pinpoint active genes within the tissue, to confirm the exact location of these developing cells. These tools revealed that the new neurons were found specifically in the dentate gyrus, a part of the hippocampus critical for learning and cognitive flexibility.

"We have now been able to identify these cells of origin, which confirms that there is an ongoing formation of neurons in the hippocampus of the adult brain," said Professor Frisen. The findings further show that adult human neural progenitor cells share similarities with those found in mice, pigs, and monkeys, though with some gene activity differences.

Interestingly, the study also found significant individual variability. While some adults had abundant neural progenitor cells, others showed very few, pointing to possible genetic or environmental influences on brain plasticity.

Reference: Ionut Dumitru et al., Identification of proliferating neural progenitors in the adult human hippocampus.Science389,58-63(2025).DOI:10.1126/science.adu9575