Brain of rats in a dream makes plans and chooses ways to achieve goals

Neuroscientists from University College London, studying the work of the brain on the example of rats, found that the consciousness of rats during periods of sleep calculates the paths of possible passage to food. Such a conclusion in their study, they made, finding the activity of brain cells responsible for navigation.

The experiment took place in a simple maze, where the straight path had two branches, only one of which had food. The rats were shown where the food is, but were not given the opportunity to reach it. Then the rats were allowed to sleep, and after that they were allowed to get to the food. During the rest of rats, scientists tracked the brain activity of animals.
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It is known that in the hippocampus there are neurons of a place (place cells) - these are neurons that are activated at the moment when the animal is in a certain place. These neurons are clearly different from others. Neurons of the place were first described also in rats in the 70s of the last century. The researchers suggested that the main function of the hippocampus of rats is the formation of a cognitive map of the environment, which contributes to the orientation of the terrain and the search for ways.

In our experiment, the neurons of the site in rats showed a special activity. In addition, it was possible to establish that it was neurons that were active, processing the choice of one of the branches - the one in which the reward was contained. Based on these results, scientists have concluded that in the brain during sleep, possible variants of future events are constructed.

The study indirectly answers the question of why people with hippocampal damage have difficulty creating new memories and planning future events. As the leader of the team of scientists, Dr. Hugo Spiers, explains, mammals, while researching a new terrain, build mental maps that are formed in the hippocampus. During sleep, he loses various routes, which helps to safely store them in memory.

“It’s interesting that before it was thought that the hippocampus is responsible only for memorization, and the neurons of the place keep the details of the places you visited,” says study co-author Freya Olafsdotter. “But it turned out that the hippocampus is also engaged in planning the future, rehearsing new paths that need to 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 it will be. Apparently, planning for the future is not only a human prerogative.