An article in the New York Times last month cited a recent study that found that children who attended music lessons at a young age reap years of benefits, even if they only play music during childhood. Perri Klass writes: 

Researchers at Northwestern University recorded the auditory brainstem responses of college students — that is to say, their electrical brain waves — in response to complex sounds. The group of students who reported musical training in childhood had more robust responses — their brains were better able to pick out essential elements, like pitch, in the complex sounds when they were tested. And this was true even if the lessons had ended years ago.

nytimes.com