Rats – they’re ubiquitous, resilient and kind of, well, disgusting. But is that all they have going for them? Not so, say researchers at University College London, who conducted a breakthrough study on the brain patterns of the noble rodents. Surprisingly, they found that while sleeping, rats “dream” up plans for what they’ll do in the future, even if those plans include venturing to never before traveled places.
The testing was pretty straightforward. Hooked up to equipment to monitor their brain activity, the rats were first placed in a T-shaped track. One end of the junction was empty, while the other had food visible in it – the catch was that the rats couldn’t get to it. They were then allowed to rest in a separate chamber.
When the rats were returned to the track, there was no barrier to the food. Predictably, they made their way to it easily, but analysis of their brain activity revealed something amazing – in their minds, they’d been there before. When the researchers looked at their brain patterns while the rats made their way to the food, they found that they were nearly identical to their brain patterns while sleeping.
Rather than simply passing out, the rats were making use of their downtime to plan ahead. It’s not unlike dreaming about winning the lottery, or an athlete dreaming about making a big play.
“During exploration, mammals rapidly form a map of the environment in their hippocampus,” says senior author Dr Hugo Spiers (UCL Experimental Psychology). “During sleep or rest, the hippocampus replays journeys through this map which may help strengthen the memory. It has been speculated that such replay might form the content of dreams. Whether or not rats experience this brain activity as dreams is still unclear, as we would need to ask them to be sure! Our new results show that during rest the hippocampus also constructs fragments of a future yet to happen. Because the rat and human hippocampus are similar, this may explain why patients with damage to their hippocampus struggle to imagine future events.”
While surprising, the results aren’t 100% conclusive. In future testing, the researchers would like to establish a firm link between what the animals seem to be “planning” and what they actually do next.