Astrocytes - brain cells once thought of as supporting players to neurons - have a principal role in stabilizing memories for long-term recall. In mice, researchers found that Fos, a gene associated with cell activity, was highly expressed in the astrocytes of mice that re-entered cages they'd been conditioned to associate with fear. The team also found that highly-active astrocytes produce more receptors that respond to the neurotransmitter noradrenaline, which allows them to communicate with neurons.