A new technique for deciphering people's thoughts can now be used remotely

 Scientists can now "decipher" people's thoughts without touching their heads. Earlier methods of mind reading involved implanting electrodes deep into the human brain. The new method, described in a report published on September 29 in the bioRxiv preprint database, is based on a non-invasive brain scanning technique called functional magnetic resonance imaging (fMRI).

fMRI tracks the flow of oxygenated blood through the brain, and because active brain cells require more energy and oxygen, this information provides an indicator of brain activity. By its nature, this scanning method cannot capture real-time brain activity because the electrical signals emitted by brain cells travel much faster than blood flows through the brain.

It is worth noting, however, that the authors of the study found that they could still use this imperfect substitution to decipher the semantic meaning of human thoughts, although they could not make a literal translation.

In a new study that has not yet been peer-reviewed, the team scanned the brains of one woman and two men in their 20s and 30s. Each participant listened to a total of 16 hours of various podcasts and radio shows over several sessions at the scanner. The team then fed these scans into a computer algorithm they called a "decoder," which compared patterns in the audio recordings with patterns in recorded brain activity.

An algorithm could take an fMRI recording and generate a story based on its content, and that story matched the original podcast or radio show "quite well." In other words, the decoder could determine which story each participant heard based on their brain activity.

At the same time, the algorithm made some mistakes, such as switching character pronouns and using the first and third persons. He understands quite well what's going on, but he doesn't know exactly who's doing it. In additional tests, the algorithm was able to explain quite accurately the plot of a silent movie that participants watched in a scanner. He was even able to tell the story the participants imagined in their heads.

In the future, the research team intends to develop this technology so that it can be used in brain-computer interfaces designed for people who cannot speak or write.

The study was reported in The Scientist.