My dog Bozie spends the night sleeping at the foot of the bed snoring. Sometimes he straightens out and his feet start moving as if he’s running. Does he have a muscular disorder like restless leg syndrome? Or is he dreaming of chasing a bird outside at full speed? What is going on in the mind of a pet?
Pets dream. Aristotle observed that “It would appear that not only do men dream, but horses also, and dogs, and oxen, aye, and sheep, and goats, and all viviparous quadrupeds; and dogs show their dreaming by barking in their sleep.”
What about cats? Didn’t all the bad boys in middle school want to open up a cat to see what was going inside? French sleep researcher Michel Jouvet did exactly that. In the 1960’s, scientists believed that all dreaming took place during rapid eye movement (REM) sleep when we are essentially paralyzed, but there was increasing evidence that people moved in particular patterns while in REM sleep. Jouvet knew, as Aristotle had observed, that animals seem to dream and also that the animals experienced REM sleep and the muscle paralysis, called atonia, that goes along with it. To study what was going on in the brain of the sleeping cats during REM, he had to reverse the atonia. He split the cats’ brains open and damaged the brain stem sufficiently to defeat the atonia. The research team watched and filmed the cats as they went into a REM state called REM-A, which is REM sleep without the atonia. The cats were, indeed, asleep, impervious to the attractions of stimuli such as food or light. But in REM-A sleep, the cats would pop up and meander around, sniffing, smelling and then, remarkably, cowering as if they were the prey. They also stalked imaginary victims and devoured imaginary mice. They moved defensively, hunted invisible dream-prey, and acted aggressively. They were dreaming in cat-land. And their dreams were filled with problems and fears. While they were sleeping, the cats created scenarios based on their real, awake problems. Then they rehearsed reactions to the scenarios while they were asleep. If they were faced in real life with those same risks, they had already practiced how to react and survive .
These early experiments suggest a few lines of thought. First, the cats acted out fear and avoidance behaviors. The cats, like humans, had scary dreams.
Second, and more broadly, the cats were pursuing organized behavior like hunting, hiding, and eating, with no hope of fulfilling the behaviors while asleep. Cat dreams had a lot in common with human dreams, indicating that in both species the dream state in the brain creates chemicals that in turn help the brain cope with actual, foreseeable future challenges.
Was a dream state a way to practice behavior and reaction to specific stimuli?
With the advance of technology, we had better ways to peer into the brains of animals. MIT scientists K. Louise and M.A. Wilson monitored the neurons in the brains of rats when they were awake and running in mazes. Then they monitored the rats when they were in REM sleep. The same neurons that fired when the rats were actually running the maze also fired when they were dreaming, and in the same order. The rats were forming a map of the maze and creating new memories in the hippocampus. They were rehearsing their non-sleep behavior.
Zebra finches are birds known for their melodious singing. Researchers wanted to find out whether the birds are born with a song in their brains and the simple answer is that they are not. When the birds are awake, they listen to other birds singing and learn the songs, note for note. University of Chicago researchers Amish Dave and Daniel Margoliash mapped the brains of the birds while they were learning their song, then mapped the same section of their brain while asleep. The same neurons that were firing when the birds were awake and studying the song also fired when they were asleep. The finches learned their songs by rehearsing them silently in their sleep. Were the birds “paralyzed” in sleep, unable to do more than fire the same neurons? Some twenty years later the results are in. The researchers attached electrodes to the finch’s’ vocal muscles and found that the muscles move the same way as they would while awake to sing the songs. The birds can also create new songs by improvising versions of the song and anticipate future notes in their sleep.
We know that humans sleep and dream, and many of those dreams are hypothetical scenarios of real world challenges. Like stories, dreams are about problems. Cat dreams had a lot in common with human dreams, indicating that the dream state in the brain creates chemicals that in turn help the brain cope with actual, foreseeable future challenges. Memorized songs are the key means of communication and survival in their waking lives for zebra finches. We know that zebra finches use their minds and their bodies while they are sleeping to rehearse and memorize the songs. We know that during sleep, animals mentally rehearse in scenarios they may face in the real world. The brain fires neurons in networks that embody the reactions to those scenarios. Those patterns are learned, and the reactions rehearsed in sleep are available if needed in the real world.
These studies advance a powerful way to view our human dreams. When we dream, we present ourselves with versions of real world problems and our brains fire neurons in a pattern or network that embody reactions to these challenges. We practice and learn optimal reactions to actual threats. We are training our responses to real life challenges while we are asleep. The more we train, the better and more efficient we get and the more likely we will succeed in real life. We have a physiological mechanism that creates scenarios and narratives when there are no significant inputs from the external world. Our brains are story machines that go to work when we are asleep.
This research suggests two important conclusions. First, our dreams are a form of simulation of the real world where we rehearse our behaviors to improve our skills in real life. Second, we generate these valuable simulations with the basic units of universal story structure from deep within our non-conscious brain. We are generating stories in which we are the main characters, the protagonists, and we are facing the obstacles we ourselves envision we must overcome. No wonder stories are so powerful. Our brains are story making machines.