You swallow the pill. As it works its way through your digestive system, it slowly releases its chemical payload, which travels through your bloodstream to your brain. A biochemical chain reaction begins. Old disused nerve cells spring into action and form new connections with each other. And amazingly, lost memories start to flood back.

The idea of a pill for memory loss sounds like pure science-fiction. But scientists from the Massachussetts Institute for Technology have taken a first important step to making it a reality, at least for mice.

They used a special breed of mouse, engineered to duplicate the symptoms of brain diseases that afflict humans, such as Alzheimer’s. The mice go about their lives normally, but if they