The brain of rats in a dream makes plans and chooses ways to achieve goals
Neurophysiologists from University College London, studying the work of the brain on the example of rats, found that the consciousness of rats during sleep periods calculates the paths of a possible passage to food. They made such a conclusion in their study by detecting the activity of brain cells responsible for navigation.
The experiment took place in a simple maze, where the direct route had two branches, only one of which had food. The rats were shown where the food is, but were not given the opportunity to get to it. Then the rats were allowed to sleep, and after that they were allowed to get to the food. While resting rats, scientists tracked the brain activity of animals.
It is known that in the hippocampus there are place neurons(place cells) - these are neurons that are activated when the animal is in a particular place. These neurons are clearly different from others. Place neurons were first described in rats in the 70s of the last century. Researchers suggested that the main function of rat hippocampus is the formation of a cognitive map of the environment, which helps to orientate on the ground and find ways.
In our experiment, rat site neurons showed particular activity. In addition, it was possible to establish that it was neurons that were active that processed the option of choosing one of the branches - the one that contained the reward. Based on these results, scientists concluded that possible options for future events are constructed in the brain during sleep.
The study indirectly answers the question of why people with hippocampal damage have difficulty creating new memories and planning future events. As the team leader, Dr. Hugo Spiers, explains, mammals build mental maps that form in the hippocampus while exploring a new area. During sleep, he plays various routes, which helps to reliably put them into memory.
“Interestingly, it used to be thought that the hippocampus is only responsible for remembering, and the neurons of the place store the details of the places you visited,” says study co-author Freya Olafsdotter. “But it turned out that the hippocampus is also planning the future, rehearsing new paths that must be followed in order to achieve food.”
It turns out that the hippocampus not only records everything that has already happened, but also plans what else will happen. Apparently, planning for the future is not only a human prerogative.
