Applying a gentle electric current to the brain during sleep can significantly boost memory, researchers report. A small new study showed that half an hour of this brain stimulation improved students’ performance at a verbal memory task by about 8%. The approach enhances memory by creating a form of electrical current in the brain seen in deep sleep, the researchers suggest.Jan Born at the University of Luebeck in Germany, and colleagues, recruited 13 healthy medical students for the study and gave them a list of word associations, such as “bird” and “air”, to learn late in the evening. Afterwards, researchers placed two electrodes on the forehead and one behind each ear of the volunteers and let them sleep.The students’ various sleep stages were monitored using an electroencephalogram (EEG) machine. When the students entered a period of light sleep, Born’s team started to apply a gentle current in one-second-long pulses, every second, for about 30 minutes. The EEG readings revealed that this current had put students into a deeper state of sleep.The next morning, the students performed about 8% better on the word memory test than when they underwent the same type of memory experiment without brain stimulation.Born believes this memory boost was due to the pattern of the applied current mimicking that seen in naturally occurring deep sleep, where memory consolidation is thought to take place.