Endogenous opioid release during play enhances the prefrontal cortex's executive functions.

“Play evokes small amounts of opioid release into the system. They kind of dope you up a little bit... And in fact exogenous opioids as we now know, are potentially very hazardous... but these endogenous opioids are released in children and adults anytime we engage in play. And that turns out to be a very important chemical state because there's something about having an abundance of these endogenous opioids released into the brain that allows other areas of the brain, like the prefrontal cortex, the area of the front that's responsible for what we call executive function.”

“And when the perryqueductal gray releases these indogenous opioids during play, the prefrontal cortex doesn't get stupid. It actually gets smarter. It develops the ability to take on different roles and explore different contingencies.”