Researchers have used light to disconnect the memory of an experience from that of the location where it occurred.

'Place' cells in the brain fire when the animal is in a particular location, helping it to remember that place. Stéphanie Trouche and David Dupret at the University of Oxford, UK, and their colleagues wired up the brains of mice to monitor these cells and switch them off using light. When the researchers switched off the place cells that were associated with one of two differently shaped enclosures, they found that a group of previously silent place cells fired instead to encode that location.

The team injected mice in one enclosure with cocaine, which made the animals prefer that location. When the initially active place cells were switched off, the mice no longer sought out the cocaine-linked enclosure — yet behaved as if it were still familiar.

Nature Neurosci. http://doi.org/bcsv (2016)