Scientists have discovered a way to read minds by scanning brain activity.

Researchers at the University of California at Berkeley have developed a mind-reading technique that allows them to accurately predict seen images from brain activity.

Not such a science-fiction fantasy after all, the computerised analytical tool may soon enable real or imagined images in the brain to be shown on a visual display screen – possibly even from dreams or memory.

Writing in the journal Nature, the scientists, led by Dr Jack Gallant from the University, said: “Our results suggest that it may soon be possible to reconstruct a picture of a person’s visual experience from measurements of brain activity alone. Imagine a general brain-reading device that could reconstruct a picture of a person’s visual experience at any moment in time.”

The technique relies on functional magnetic resonance imaging (fMRI), a standard technique that creates images of brain activity based on changes in blood flow to different brain regions.

With two of the scientists acting as volunteers, they viewed a total of 1,750 natural images. The data obtained was used to construct mathematical descriptions of “voxels” in the brain – the “points” that make up a 3D thought image.

Each volunteer then viewed a new set of 120 images while having their brains scanned. Combining the new data with the mathematical descriptions created earlier, the scientists were able to identify which images had been seen.

This saw the researchers achieve 92% and 72% accuracy in predicting the120 images viewed by the two volunteers. Left alone to chance, their performance would have only been 0.8% accurate.

The team have warned however about potential privacy issues in the future when scanning techniques improve: “It is possible that decoding brain activity could have serious ethical and privacy implications downstream in, say, the 30 to 50-year time frame,” said Professor Gallant. “[We] believe strongly that no one should be subjected to any form of brain-reading process involuntarily, covertly, or without complete informed consent.”

For more information, visit: www.nature.com