Rats are like humans? We share the same trait

Is the ability to imagine places and objects solely a human trait? American researchers have provided evidence that it's not. As it turns out, rats are also capable of imagination, an ability determined through virtual reality technology and brain scanners.

It's common for humans to lose themselves in their imaginative world, able to recall a range of situations, places, people, and objects in their memory. Scientists from Janelia Research Campus in the United States discovered that similar abilities are also demonstrated by certain animals, notably rats.

In affirming this, the research team developed an intricate system comprising a virtual reality kit and a scanner that measures the brain activity of rats. This apparatus recorded the functioning of a brain structure known as the hippocampus, correlating it to the rat's location within virtual reality.

The hippocampus, according to scientists, constructs mental maps of the surroundings and plays a pivotal role in the process of recalling past events or envisaging the future. The research results were published in Science.

Rats were positioned in running wheels fitted with a VR system on their heads, allowing them to undertake a virtual journey through diverse landscapes. The rodents received food rewards upon reaching a virtual goal. Concurrently, researchers recorded the animals' brain activity, assisting them in understanding the brain processes associated with a particular scenery.

In the succeeding phase of the experiment, rats were given a treat as a reward if they reached the same destination, only this time in their imagination (captured by the same scanner). This is akin to a human contemplating the route they will take, say, to the grocery store.

In the final phase of the experiment, known as the "Jedi" task, rats were rewarded when they manipulated an object in the virtual reality world using solely their imagination.

These experiments demonstrated that rats can precisely manipulate the functioning of their hippocampus — similar to humans. They can also maintain specific brain activity for several seconds, this suggests their ability to hold specific mental images like their location in space.

This mirrors the duration humans take to relive previously experienced events or formulate new ones.

"Rats can create a mental representation of places and environments without physically being there. Even when their body is immobile, their thoughts can revolve around these places," says Dr. Chongxi Lai, a co-author of the study.

"Imagination is among the most remarkable abilities of humans. But now, we have established that animals can also utilize it and we have devised a way to test it," highlights another scientist, Dr. Albert Lee.