If you've not yet seen Christopher Nolan's 2010 blockbuster Inception, it involves a group of people who travel between worlds in their minds - down a rabbit hole of layered dreams, each with their own vivid location. Such mind-bending mental teleportation may not be as far-fetched as you think, because scientists in France have managed to achieve a similar effect in mice.
Here's how it worked: after monitoring mice in specific locations, the researchers were able to identify specific cells that were activated in specific parts of their brains. This allowed them to figure out which brain cells referred to which place. Then, while the mice were sleeping, they identified brain patterns relating to the locations the mice had visited that day, and manipulated them using electrodes to create positive associations. Upon waking, the mice headed straight for the location that had been linked to a reward in their dreams.
It's not quite on the same level as Leonardo DiCaprio and Ellen Page hurtling through a surreal landscape as it collapses around them, but it's a step in that direction - and the research could eventually reveal a great deal about the way we dream, the associations we have with particular places, and the methods our minds use to tell us where we are.
"The mouse develops a goal-directed behaviour to go towards the place," study author Karim Benchenane, from the Industrial Physics and Chemistry Higher Educational Institution in Paris, told Jessica Hamzelou at New Scientist. "It proves that it's not an automatic behaviour. What we create is an association between a particular place and a reward that can be consciously accessed by the mouse."
"Even when those place cells fire in sleep, they still convey spatial information," adds Benchenane. "That provides evidence that when you've got activation of place cells during the consolidation of memories in sleep, you've got consolidation of the spatial information."
According to the researchers, these same techniques could one day be used to alter memories, perhaps suppressing the knowledge of a traumatic event.
"The mouse is remembering enough abstract information to think 'I want to go to a certain place', and go there when it wakes up," neuroscientist Neil Burgess of University College London explained to New Scientist. "It's a bigger breakthrough [than previous studies] because it really does show what the man in the street would call a memory – the ability to bring to mind abstract knowledge which can guide behaviour in a directed way."
The new research by Benchenane and his team has just been published in Nature Neuroscience.