Could rats have the power of imagination?

New research suggests that rats are able to mentally revisit places they have been to before.

As human beings, we take for granted our ability to mentally ‘time travel’ by revisiting treasured memories of good times with friends or holidays. Exciting new research published this month suggests that we may not be alone in this ability to mentally recreate what is not in front of us.

You may be familiar with Maguire’s study of London taxi drivers whereby the posterior hippocampus was found to increase in volume in those taxi drivers who had several years of experience. London taxi drivers can imagine a route, for example, from Buckingham Palace to King’s Cross station, and mentally follow this as they drive.

Researchers were interested in investigating this ability in animals; however, we cannot simply ask animals to imagine somewhere they have been before and measure their brain activity. Lai et al (2023) devised a way to study this complex idea by implanting electrodes directly into rats’ brains and then conducting a sequence of studies on them.

Initially, the rats were placed on a treadmill ball and navigated their way around a virtual reality (VR) arena in pursuit of a goal (different 3D shapes), for which they received a reward of sugar water. As the rats moved around the arena the electrode activity was carefully monitored with different locations in the arena corresponding to specific electrode activity. This initial phase meant that the researchers knew which areas of the arena the rats were thinking about (every 100 milliseconds) based on their brain activity.

In the next phase, the treadmills were still present but no longer resulted in movement around the arena, the rats could only move around by using their brains to think about where they would like to navigate. It was found that the rats were able to succeed at this task. Finally, the researchers introduced a ‘Jedi’ task where the rats were themselves stationary and had to move an object through the VR arena to reach a goal using only their thought processes, once again, the rats were able to do this.

Suggested Activities

Consider the following questions as part of your classroom discussion:

• Which type of reinforcement was used in the study by Lai et al (2023)
• The electrodes provided information within 100 milliseconds of the rats thinking about the area of the maze they wanted to visit, using any knowledge you have on methods of studying the brain, what comments could you make about the temporal resolution of this method?
• Do you think that the widely reported interpretation of this study that rats have ‘imaginations’ is accurate? Why / why not?

Read: https://www.theguardian.com/sc...

Read: Chongxi Lai, Shinsuke Tanaka, Timothy D. harris and Albert K. Lee (2023) Volitional activation of remote place representations with a hippocampal brain–machine interface. Science 382 (6670) p566-573