Scans of the part of the brain responsible for memory have for the first time been used to detect a person’s location in a virtual environment. Using functional MRI (fMRI), researchers decoded the approximate location of several people as they navigated through virtual rooms.

This finding suggests that more detailed mind-reading, such detecting as memories of a summer holiday, might eventually be possible, says Eleanor Maguire, a neuroscientist at University College London.

Her team trained its scanner on the hippocampus, a region of the brain critical to the formation and storage of memories. It is known that in animals, specialised place cells in the hippocampus fire regularly as they move from place to place.

Firing patterns

To see if these firing patterns could be read out, Maguire’s team adapted a computational technique previously used to predict the image a person is gazing at and even their intentions.


Maguire’s study is more ambitious than this past research, which she says homed in on brain areas that represent information rather predictably. “The visual cortex is very interesting but quite well behaved, whereas the hippocampus is a bit more mysterious,” she says. Place cells are strewn through the hippocampus in no obvious arrangement.

The researchers scanned the brains of four young men as they moved to and from eight locations – four each in equivalent locations in two different-coloured virtual rooms. The subjects were told to look down at the floor when they reached their prescribed location to deny their brain any access to visual giveaways to their location.

Spatial information

A computer analysis of these initial brain scans revealed predictable patterns of activity in each subject’s hippocampus. This allowed the researchers to scan the brains of their volunteers and determine which of the four locations each had been in, as well as which room.

“This is a very interesting case because it was previously believed impossible to decode [spatial] information,” says John-Dylan Haynes, a neuroscientist at the Bernstein Center for Computational Neuroscience in Berlin, Germany.

“There must be some hidden structure in the spatial organisation of cells with activity related to each of the places in the environment,” agrees Edvard Moser, a neuroscientist at the Norwegian University of Science and Technology in Trondheim.

Future techniques

Reading more precise locations or other kinds of memories could be difficult, because fMRI resolves the activity of thousands of neurons at a time, Haynes says. “One day a new imaging technique could come along and you’d be at the right place to decode even in these challenging cases,” he adds.

However, Maguire isn’t waiting for new technologies. Her team is already looking into the possibility of reading more vivid memories of events and planned movements. “We’ve done some work about how the hippocampus is involved in planning the future – where you’re going and what you’re doing.”

Journal reference: Current Biology, DOI: 10.1016/j.cub.2009.02.033