Revving up recall while fast asleep

Scientists have discovered a way to give memory a modest lift while people slumber. Application of a gentle electrical current to the scalp, which nudges sleepers into a particular phase of sleep, boosts recall the next day for recently learned facts, say neuroscientist Jan Born of the University of Lübeck in Germany and his colleagues.

Born’s team explored a particular sleep phase called slow-wave sleep, which some researchers suspect enhances learning (SN: 6/26/04, p.