It may be possible to "read" a person's memories just by looking at brain activity.
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Wellcome Trust scientists show that our memories are recorded in regular patterns, a finding which challenges current scientific thinking.
Demis Hassabis and Professor Eleanor Maguire at the Wellcome Trust Centre for Neuroimaging at University College London have previously studied the role of a small area of the brain known as the hippocampus which is crucial for navigation, memory recall and imagining future events. Now, the researchers have shown how the hippocampus records memory.
When we move around, neurons known as "place cells", located in the hippocampus, activate to tell us where we are. Hassabis, Maguire and colleagues used an fMRI scanner to examine the activity of these places cells as a volunteer navigated around a virtual reality environment.
The data were then analysed by a computer. "We asked whether we could see any interesting patterns in the neural activity that could tell us what the participants were thinking, or in this case where they were. Surprisingly, just by looking at the brain data we could predict exactly where they were in the virtual reality environment. In other words, we could 'read' their spatial memories," explains Professor Maguire, a Wellcome Trust Senior Research Fellow.
Earlier studies in rats have shown that spatial memories are recorded in the hippocampus, but these animal studies, which measured activity at the level of individual or dozens of neurons at most, implied that there was no structure to the way that these memories are recorded. "fMRI scanners enable us to see the bigger picture of what is happening in people's brains," says Maguire.
"By looking at activity over tens of thousands of neurons, we can see that there must be a pattern to how these memories are encoded. Otherwise, our experiment simply would not have been possible to do."
Professor Maguire believes that this research opens up a range of possibilities of seeing how actual memories are encoded across the neurons, looking beyond spatial memories to more enriched memories of the past or visualisations of the future.
"Understanding how we as humans record our memories is critical to helping us learn how information is processed in the hippocampus and how our memories are eroded by diseases such as Alzheimer's. It's also a small step towards the idea of mind reading, because just by looking at neural activity, we are able to say what someone is thinking," added Demis Hassabis.
So, if you are interested when, where and what will be published on our website, you have two choices: buy and fMRI or come regularly and read. Just to let you know, we don't allow fMRI in our office :-) ■