A recent study conducted by researchers at the National Institute on Deafness and Other Communication Disorders (NIDCD) sheds a light on what goes on inside of someone's brain while partaking in "spontaneous lyrical improvisation." The scanned image (shown left) compares the results of an A/B test during which subjects were instructed to freestyle (first row) and recite well-rehearsed verses (second row) to an identical 8-bar background track. For the full-length report, read "Neural Correlates of Lyrical Improvisation: An fMRI Study of Freestyle Rap."