Mike Eagle might be in the car or the shower or on stage when it hits him. A thought evolves into a freestyle rap and the rapper, better known as Open Mike Eagle, follows the lyrical trail. Freestyle, a spontaneous rap either in the middle of a written rap or on its own, remains one of the few unscripted lyrical art forms. While freestyle allows rappers to show off skills and entertain, it is also helping researchers understand how creativity works in the brain. …

Braun and his colleagues at the NIH asked 12 rappers, who had experience freestyling, to rap in an fMRI machine. Each rapper memorized a few lines of a rap written by a friend of Eagle’s, N/A, and performed it for about a minute. Then they freestyle rapped for a minute. The researchers compared the brain activity between the freestyle and conventional performances. …

When the rappers freestyle rapped, activity in the medial prefrontal cortex (which is responsible for self-interested behavior) increased, while activity in the dorsolateral cortex (which regulates executive function), decreased. Also, while the rappers freestyled, the medial prefrontal cortex networked with other areas, including regions responsible for language and the amygdala, which plays a role emotions. And even though Eagle associates movement with freestyling, the brain did not show any increased activity in areas responsible for motor activity.