The ability to transport oneself to other places or moments with one's thoughts was, until now, an ability that was believed to be reserved for humans, but a group of researchers discovered that rats also have imagination.
To achieve this discovery, scientists at the Howard Hughes Medical Institute's Janelia Research Center, in Virginia (United States), they developed a type of “thought detector”, capable of measuring, in real time, the neuronal activity of rats and translating its meaning, this medical institute revealed this Thursday.
The system combines 360-degree virtual reality and a brain-machine interface (BMI) to probe rats' inner thoughts by measuring electrical activity in the hippocampus, the region of the brain where memories are stored and generated.
When the brain is remembering, there is a specific activity in the hippocampus related to this activity, but until now it has not been detected in animals.
The system allowed researchers to see how, like humans, when rodents experience places and events, specific patterns of neuronal activity are activated in their hippocampus.
Scientists thus discovered that a rat can activate hippocampal activity just by thinking about a place, without physically moving, that is, by imagining it.
As the first phase of the experiment, the researchers created a kind of “thought dictionary” that allowed them to decode the rat's brain signals when it experienced something.
They then carried out two tests, which were 'christened' with cinematic names.
In one of these, called “Jumper”, in homage to the film and book whose protagonist has the ability to teleport, the mouse was introduced into the system and while walking on a spherical belt, its movements were reflected on the 360-degree screen. When he achieved his goal, he was rewarded.
The system recorded the activity of the rat's hippocampus and showed how its neurons are activated when the rat 'navigates' to reach the target.
The end result is that the animal uses its thoughts to reach the reward, first thinking about where it needs to go to get it, an imaginative process that people experience regularly.
In the second experience, called “Jedi”, in homage to the Star Wars saga, the mouse is fixed in a virtual location and moves an object to a location just by thought, in the same way that someone sitting down can imagine getting up to pick up a cup. of coffee, without moving.
The researchers then changed the target location, requiring the animal to produce activity patterns associated with the new location.
The team discovered that mice can precisely and flexibly control hippocampal activity, just like humans.
Furthermore, animals are able to maintain this activity in the hippocampus for several seconds, a time similar to the time it takes humans to relive past events or imagine new scenarios.
“Imagining is one of the most extraordinary things humans can do. Now we discovered that animals can do this too and we found a way to study it”, highlighted one of the researchers, Albert Lee.
The study also showed that the brain-machine interface (BMI) system can be used to probe hippocampal activity, which represents a major advance in the study of this important region of the brain.