Preachers, the good ones, do the same thing. For that matter, classical musicians playing from the score, they can flow too. Flow is about performance is about flow.Freestyling is to rap as improvisation is to jazz. Rather than reciting a pre-written rhyme, or reading off pages of sheet music, the artist stands up onstage and channels the Muse directly, no filter: whatever comes up, comes out. ... Freestyle and improv demand a particular kind of genius. Watch enough YouTube videos of jam sessions at the Blue Note or rap battles at ScribbleJam, and you begin to recognize the sight of a performer lost in the creative process: the droopy eyes, the nodding head, the trance-like sway. They’ve left planet earth and entered a flow state.
Here's what the brain's up to:
When an artist was freestyling, rather than rapping conventionally, there was a marked activation of the medial prefrontal cortex (mPFC) and a deactivation of the lateral prefrontal cortex (LPFC).
As coauthor Allen Braun, head of the NIH’s language section, explains, “A simple way to looking at it is that the medial portions of the prefrontal cortex”—those parts that lit up on the fMRI—“are involved in motivation, organization, and drive towards a behavior.” In other words, freestyling depends heavily on those functions.