Study: Rats Dream About Running Mazes

B O S T O N, Jan. 24 -- Some rats apparently can't ever escape the rat race,even when they're sound asleep.

Researchers at the Massachusetts Institute of Technology saythey've entered the dreams of rats and found them busily workingtheir way through the same lab mazes they negotiated during theday. It's evidence not just that animals dream — most pet owners knowthat — but that they have complex dreams, replaying events much theway humans do, researchers said. And they may use their dreams tolearn or memorize. The discovery, announced today, could eventually helpresearchers understand how the human mind works in the murky worldof the subconscious. "It's really opening a new door into the study of dreams,"said Matt Wilson, associate professor at MIT's Center for Learningand Memory, and lead researcher of the study, reported in Friday'sissue of the journal Neuron. "It's not just a step forward, it's astep into a new domain."

Right Results, Wrong Specifics?

But Robert Stickgold, assistant professor of psychiatry atHarvard Medical School, said that while Wilson's research providesimportant evidence of sleep's role in memory, there's no way toprove MIT researchers were seeing rats dream. That's because the link between the rats' brain patterns andactual dreaming can't proved, he said. "He's got the right results, he's just got the wrong species,"Stickgold said. "If the rat would tell us, 'Yes, I was dreamingabout running around the track,' then we'd have it nailed down." "This is a good as it can get at this point," he added. The four-year study initially focused on memory, withresearchers measuring brain activity of rats during various tasks.But after Wilson checked the rats' brain activity while sleeping,he found nearly identical brain patterns in dreaming and wakingstates. "At that point, it was kind of like a lightning bolt," hesaid.

Dreaming About the Rat Race?

For the next two years, researchers worked to prove theimplications of the initial observation — that the rats weredreaming about their daily experiences.