The Dream Episode: What Happens When Your Brain Keeps Working

Josh and Chuck open this episode in a state that anyone who has ever been abruptly wrenched from sleep will recognize: Josh had been dreaming six minutes before recording, woke up, splashed water on his face, and came straight to the microphone. Chuck had a dream about Rachel Dratch at a New York art opening that morning. Jerry the producer was apparently still asleep. It is, as Josh puts it, "a good old fashioned Stuff You Should Know episode" — the main topic they had done five subtopics on without ever covering the thing itself.

What Dreams Are Made Of

The conversation starts with the mechanics. REM sleep was only discovered in the 1950s, and it turns out that during REM, your body essentially paralyzes itself so you don't physically act out your dreams. For a long time, researchers suspected that rapid eye movement corresponded to where you were looking in your dream, but they couldn't prove it. Then scientists cracked open the heads of mice and found that eye direction during REM matched where the mouse's "dream eyes" were looking. A separate study with lucid dreamers had them trace circles with their thumbs in their dreams; when they imagined looking at the circle, their eyes moved in a stuttery pattern, but when they looked at their dream thumb, their eyes moved smoothly — exactly like waking vision.