New research from scientists at the University College of London suggests that rats might be having some strange dreams when they fall asleep.
Our dreams are strange enough as it is. But what if we could tell what other animals were dreaming too? A fascinating study from researchers at the University College of London has shown how rats’ brains undergo processes when they sleep by monitoring certain neuron pairs. According to a report from the New Scientist, a sleeping rat’s brain bears many similarities to that of a human.
Rats in the study were shown a tasty prize at the end of a path that they were blocked from accessing. When some of the rats got frustrated or distracted and fell asleep for a nap, their brains came alive with a flurry of activity, as if they were actually dreaming about the food they had just seen but couldn’t reach.
Dr. Hugo Spiers, the study’s head author, explains “It’s like looking at a holiday brochure for Greece the day before you go – that night you might dream about the pictures.”
Rats create mental maps of their environments in the hippocampus, one of two curved structures on the sides of the brain. Electrodes were hooked up to the rats’ hippocampi, which revealed how different locations are recorded and stored by specific neuron-pairs firing. These neuron pairs, or“place cells,” fire not only when a rat returns to a place it recognizes, but also when it sleeps.
To test the theory that the rats in the study were actually dreaming about the food that they couldn’t reach, Spiers and his team put four of them at the bottom of a T-shaped maze. The top of the “T” was cut off by a grill, and there was a piece of food visibly placed at one end of the arm of the maze.
As the rats became frustrated at the inaccessible food, the scientists removed them from the maze and put them in a cozy nest, where they quickly fell asleep and began to show an increased level of activity in the same place cells in the hippocampus. When the rats were placed back in the maze with the grill blocking the food removed, they wasted no time going straight for the treat.
We can’t say for sure whether the rats in the study experienced dreams in the same way that humans do, but it showed that a similar part of the brain was activated around a stimulus while the rats were both awake and asleep. The study offers fascinating insights into the study of sleep, and shows that animals just might have dreams in their sleep too.