Washington University scientists have managed to connect people's brains directly to a computer, allowing the computer to listen to their thoughts.
With no prior training, patients were able to simply think a series of words for the cursor to respond.
The team used a technique that's usually used to identify epilepsy. Electrocortiography (ECoG) involves the placing of electrodes directly onto a patient's brain to record electrical activity.
Four patients who suffered from epilepsy were given a craniotomy to place an electrode onto their brains. This emitted signals which were acquired, processed, and stored on a computer.
The patients sat in front of a screen and attempted to move a cursor toward a target using pre-defined words that were associated with specific directions. For instance, saying or thinking of the word "AH" would move the cursor right.
The results showed 90 percent accuracy.
"This is one of the earliest examples, to a very, very small extent, of what is called 'reading minds' - detecting what people are saying to themselves in their internal dialogue," says lead author Dr Eric C Leuthardt.
The study was the first to demonstrate microscale ECoG recordings, and implies that future operations could use a very small and minimally invasive implant.
It also showed that thoughts can be acquired from a site that's less than a centimeter wide, requiring only a small insertion into the brain, and greatly reducing the risk of the surgical procedure.
"We want to see if we can not just detect when you're saying dog, tree, tool or some other word, but also learn what the pure idea of that looks like in your mind," says Dr Leuthardt.
"It's exciting and a little scary to think of reading minds, but it has incredible potential for people who can't communicate or are suffering from other disabilities."