A “switch” for memories

Our experiences leave traces in the brain, stored in small groups of cells called “engrams”. Engrams are thought to hold the information of a memory and are reactivated when we remember. A team led by Professor Johannes Gräff at EPFL’s Laboratory of Neuroepigenetics combined CRISPR-based gene control with a technique that tags engram cells in mice. The mice were then trained to link a specific place with a mild electric shock to the paws. The researchers were able to show that CRISPR inhibition of the Arc gene in engram cells prevented the mice from learning, while boosting it made their memory stronger.