Interestingly, the large portion responsible for monitoring one’s performance (dorsolateral prefrontal cortex) shuts down completely during improvisation, while the much smaller, centrally located region at the foremost part of the brain (medial prefrontal cortex) increases in activity. The medial prefrontal cortex is involved in self-initiated thoughts and behaviors, and is very active when a person describes an event that has happened to him or makes up a story. The researchers explain that, just as over-thinking a jump shot can cause a basketball player to fall out of the zone and perform poorly, the suppression of inhibitory, self-monitoring brain mechanisms helps to promote the free flow of novel ideas and impulses. While this brain pattern is unusual, it resembles the pattern seen in people when they are dreaming.
via cdm