It’s been known for a while that sleep helps consolidate certain memories; that’s probably a major purpose of sleep. But the latest experiments by Harvard Medical School researchers show that a good night’s rest can enhance your performance as much as 20-30 percent. Not all memories, just those of motor skills such as riding a bicycle, throwing a ball, or playing the piano. Still, it’s a big finding, especially when combined with what happens next. Reactivating the memory will cause it to destabilize – become somewhat plastic. At first that sounds bad, but when you think about it, you don’t want motor memories that you can’t change. “There have been hints from animal studies that certain emotional memories, such as fear, become vulnerable to change when reactivated,” says Matthew Walker, a neuroscientist who led the experiments. “But such reformation had never been shown in humans before. It’s a most exciting discovery.” The new findings could have practical applications like helping stroke victims regain basic motor skills, enhancing sports and music-playing capabilities, and ridding people of phobias and unwanted stressful memories. Details were published in the Oct. 9, 2003 issue of the British science journal Nature. The researchers included Tiffany Brakefield, Allan Hobson, and Robert Stickgold.