Now scientists can “decode” people’s thoughts without touching their heads, reported scientist. Previous mind-reading methods relied on placing electrodes deep inside people’s brains. The new method, described in a report published Sept. 29 in preprint database bioRxiv, relies instead on a non-invasive brain scanning technique called functional magnetic resonance imaging (fMRI).

MRI monitors the flow of oxygenated blood in the brain, and this information provides an indirect measure of brain activity, as active brain cells require more energy and oxygen. Due to its nature, this scanning method cannot record brain activity in real time because the electrical signals released by brain cells travel much faster than blood moves through the brain.

But what’s surprising is that the study authors discovered that even if they weren’t able to produce a literal translation, people could still use this imperfect proxy to decipher the semantic meaning of their thoughts.

“If you had asked any cognitive neuroscientist in the world 20 years ago if this was possible, they would have laughed at you,” he said. Scientist is a senior author. Oleksandr Khat, a neuroscientist at the University of Texas at Austin.

For the new study, which has not yet been peer-reviewed, the team scanned the brains of a woman and two men in their 20s and 30s. Each participant listened to 16 hours of different podcasts and radio shows over several sessions in the browser. The team then fed these scans into a computer algorithm they called a “decoder” that compared patterns in the sound with patterns in recorded brain activity.

Huth said an algorithm could take an fMRI recording and create a story based on its content, and that story would match “pretty well” with the original plot of the podcast or radio show. scientist.

In other words, the decoder can determine which story each participant heard based on their brain activity. With all this, the algorithm made some mistakes, such as changing character pronouns and using the first and third person. “He knows pretty well what’s going on, but he doesn’t know who did it,” Huth said.

In additional tests, the algorithm was able to accurately describe the plot of a silent movie that participants watched in a browser. He could even tell the story the participants imagined in their minds. In the long term, the research team aims to develop this technology for use in brain-computer interfaces designed for people who cannot speak or write.