Scientists already know how to see into your mind's eye, and now they can hear the voices in your head. In a new paper published in PLoS Biology, researchers present evidence showing that they can track the brain activity of a person listening to spoken words and use it to reconstruct the words.
Has Big Brother arrived? Not quite. The University of California, Berkeley scientists behind the study didn't actually read minds. They only "eavesdropped" on words that subjects were actually hearing. But it may not be so hard to apply the research to words we imagine. "There is some evidence that hearing the sound and imagining the sound activate similar areas of the brain," said study co-author Brian N. Pasley, a post-doctoral researcher at the university.
In any case, the scientists focused less on potentially nefarious uses of the technology and more on how the technology could be used to develop treatments for medical conditions that make normal speech impossible. The paper found that "it may be possible to readout intended speech directly from brain activity" and that the research is "huge for patients who have damage to their speech mechanisms because of a stroke or Lou Gehrig's disease and can't speak," said study co-author Robert Knight, a professor of psychology and neuroscience at the university.
According to a statement released by the university, the researchers
"enlisted the help of people undergoing brain surgery to determine the location of intractable seizures so that the area can be removed in a second surgery. Neurosurgeons typically cut a hole in the skull and safely place electrodes on the brain surface or cortex – in this case, up to 256 electrodes covering the temporal lobe – to record activity over a period of a week to pinpoint the seizures. For this study, 15 neurosurgical patients volunteered to participate."
The scientists recorded brain activity as a subject listened to 5-10 minutes of conversation, matched up parts of the brain activity images with parts of the sounds, and could then reconstruct various words the patient heard.
In other words, once they learned how a given patient processes information from sound to mental image, the researchers were able to reverse the process and turn a mental image into the sound that created it.
According to MedicalXpress,
"[Pasley] compared the technique to a pianist who knows the sounds of the keys so well that she can look at the keys another pianist is playing in a sound-proof room and "hear" the music, much as Ludwig van Beethoven was able to "hear" his compositions despite being deaf."