Rats are able to plan for the future through the use of dreams, according to a new study. The rodents picture paths to rewards, such as treats, while they sleep, the study concludes.
University College London researchers examined brains of the rodents as they rested, after seeing food they could not access. After waking, the animals were allowed to walk to the treat while brain activity was monitored.
The hippocampus is an area of the brain associated with planning for the future. Human subjects who experience damage to this region of the brain are often unable to imagine future times.
"During exploration, mammals rapidly form a map of the environment in their hippocampus. During sleep or rest, the hippocampus replays journeys through this map which may help strengthen the memory. It has been speculated that such replay might form the content of dreams. Whether or not rats experience this brain activity as dreams is still unclear, as we would need to ask them to be sure!" Hugo Spiers of UCL said.
Rats were placed at the bottom of a T-shaped path, with transparent barriers placed on each "aisle." The animals could see food at the end of one of the paths, but not the other. As the rodents slept, specific place markers were seen flashing in the brains of the animals. These provided the test animals with a "road map" to the path containing food, but not to the empty hallway. When the tiny mammals woke up, they immediately made their way to the treat. The barriers had been removed by researchers, allowing the rodents to head toward the food.
"What's really interesting is that the hippocampus is normally thought of as being important for memory, with place cells storing details about locations you've visited. What's surprising here is that we see the hippocampus planning for the future, actually rehearsing totally novel journeys that the animals need to take in order to reach the food," Freyja Ólafsdóttir of UCL Biosciences told the press.
Investigators found that the hippocampus in rats is responsible for planning future actions while the rodents sleep. This could be based on the hippocampus determining how rewards, such as food, may be obtained. This study showed that this region of the brain plans possible future actions in rats, just as it does in human beings.
Investigation of how rats plan for the future through the use of dreams was profiled in the journal eLife.
Photo: Steffan Vilcans | Flickr
