Memory Competition

Most of the brain contains cells that no longer divide and renew. However, the dentate gyrus, nestled within the memory-forming centre of the brain (the hippocampus) is one of the few sites where new cells continue to form throughout life. As a person ages, there is an ever-increasing struggle for these new dentate gyrus neurons (coloured pink) to integrate with existing older neurons (green) because the latter already has well-established connections. This may be why learning and memorisation becomes more difficult as a person gets older. Scientists have now found that by temporarily reducing the number of dendritic spines – branches of neurons that form connections with other neurons – in the mature cells, the new cells have a better chance of functionally integrating. Indeed, in live mice, briefly eliminating dendritic spines boosted the number of integrated new neurons, which rejuvenated the hippocampus and improved the animals’ memory precision.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image courtesy of Kathleen McAvoy
• Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, USA
• Copyright held by original authors
• Research published in Neuron, September 2016