Star-shaped cells in the brain called astrocytes are thought to provide biochemical support to neurons and may even be involved in neuronal communication. Now these cells have been found to play a part in the formation of long-term memories — by providing their neighbouring neurons with lactate.

Cristina Alberini at Mount Sinai School of Medicine in New York, Pierre Magistretti at the Swiss Federal Institute of Technology in Lausanne and their colleagues trained rats to avoid a part of a cage where they were likely to receive a mild electric shock.

When the researchers dripped a drug that blocks lactate formation in astrocytes directly onto the rat's brains, or when they blocked the expression of lactate transporters in the hippocampus, the rats were unable to recall which part of the cage to avoid.

Cell 144, 810–823 (2011)