This article explains nothing: Why Teenagers Are So Impulsive, but it's a good example of the nonsense that is coming from brain imaging.
The article spins the imaging data to be about crime. It's not about crime, it's just about the young male brain as compared to the female. It's not a bug, it's a feature. Young male humans are designed to defend the tribe, to kill food, and to be willing to die doing those things, but no brain scan can explain that. Vive la difference.