Scientists have discovered that animals can imagine just like humans. They found that animals can think about places and objects that are not in front of them. Genelia’s scientists discovered this by examining a rat’s inner thoughts using a combination of virtual reality and a brain-machine interface.
Scientists have found that rats, like humans, can use their thoughts to imagine walking to a location or moving a distant object to a specific location.
During recall or simulation, the hippocampus contains a visual representation of the surroundings. It is uncertain whether animals can consciously control their hippocampus activity through their worldview.
A new study suggests that the hippocampus, a part of the brain involved in spatial memory, exhibits distinct neural activity patterns in mice when experiencing places and events similar to humans. Thus, rats can intentionally develop similar patterns of activity to remember locations that are far away from their current location.
According to the authors of the study, animals, like humans, have a form of imagination.
Chongzi Lai, a postdoc in the Harris and Lee labs and first author of the paper describing the new findings, said, „The rat can actually process representations of places in the environment without going there. Even though his body is still, his spatial thoughts can go to a very distant place.
Scientists wanted to create a system to understand how animals think. They developed a real-time „thought detector” that can measure neural activity and translate its meaning. It uses a brain-machine interface (BMI) that provides a direct link between an external gadget and the brain’s activity.
Electrical activity in the rat’s hippocampal region and its location in a 360-degree virtual reality arena were linked to a computer via BMI. Using BMI, scientists can determine whether a rat has stimulated hippocampus activity. In other words, they can determine whether the animal can imagine visiting the site.
After developing this system, the scientists created a mental dictionary to decode the rat’s brain signals. It summarizes what the mouse’s activity patterns look like when it experiences something—in this case, places in the VR arena.
A mouse is used in a VR system. The mouse moves on a spherical treadmill, and a 360-degree screen shows its movements. When the rat reaches the target, it gets a reward.
At the same time, the BMI system records the hippocampus activity of the rat. As the rat moves through the arena to reach each goal, the scientists can observe which neurons light up. This data serves as the foundation for real-time hippocampal BMI, which translates on-screen activity into hippocampal activity in the brain.
The scientists disconnected the treadmill and rewarded the rat for reproducing the hippocampal activity pattern associated with the target location. BMI changes the brain activity of animals on a virtual reality screen in a „jumper” challenge. In essence, the animal thinks its way to the reward by first imagining the place it needs to reach. Humans often go through this mental process.
In another Jedi task, the mouse moves an object to a location through thought. The rat is stationary in a virtual environment but can “move” an object toward a target in the VR region by manipulating its hippocampus activity. Then, the researchers modified the target, requiring the animal to exhibit activity patterns consistent with the new platform.
Scientists have discovered that, like humans, rats have precise and flexible control over their hippocampus activity. Animals’ ability to maintain this hippocampus activity allows them to focus their thoughts on a specific location for long periods of time, similar to when people daydream or replay previous experiences.
Harris said, „What’s amazing is that our, perhaps naively, very long exposure to the rat’s attention, rats learn to think about that place and not anywhere else.”
Journal Note:
- Chongzi Lai, Shinsuke Tanaka et al. Optional activation of remote place representations with a hippocampal brain-machine interface. Science. DOI: 10.1126/science.adh5206