> Blumberg decided to put the dream-debris theory to the test. He surgically removed the rats’ cortex—the brain region, involved in visual imagery and conscious

> Blumberg decided to put the dream-debris theory to the test. He surgically removed the rats’ cortex—the brain region, involved in visual imagery and conscious experience, where dreams were believed to originate—leaving only the brain stem, which controls subconscious bodily functions, intact. The sleeping pups continued to twitch exactly as before. “There was no way that twitching was a by-product of dreams,” Blumberg told me, when we spoke last fall.