In a groundbreaking development, a team of brain specialists from the California Institute of Technology has successfully achieved the decoding of words "spoken" entirely in the brain. This pioneering brain-computer interface (BCI) approach involves recording signals from individual neurons in real time, making it the first of its kind.

The study, which was reported in the esteemed journal Nature Human Behavior, focused on implanting probes in a previously unexplored region of the brain called the supramarginal gyrus (SMG). This innovative BCI technology was tested on two volunteers with tetraplegia, and the findings have been outlined in a Research Briefing published by Nature Human Behavior.

Over the years, researchers have made strides in developing technology that can decipher an individual's thoughts and convert them into written words on a computer screen. However, previous BCI technologies had limited capabilities, often relying on trained speech interpreters and testing in individuals who were also speaking.

This new study took a significant step forward by targeting a different area of the brain, allowing the researchers to decode words that were solely "spoken" within the brain. Specifically, the team implanted electrodes in the supramarginal gyrus, a region that recent research suggests is involved in subvocal speech.

After a two-week healing period for the volunteers, the researchers collected data using the BCI, which had been trained to recognize brain signals associated with six test words and two control words with no meaning. The volunteers were instructed to imagine speaking the words displayed on a computer screen while their brain signals were decoded.

The results were impressive, with one patient achieving a remarkable 79% accuracy in decoding the "spoken" words, while the other patient achieved 23% accuracy. Although both efforts were deemed successful, the researchers were unable to explain the substantial difference in performance between the volunteers.

This groundbreaking research represents a significant leap in the field of BCI technology, showcasing the potential to decode words directly from the brain, without the need for external speech production. The implications of this breakthrough are vast, offering hope and possibilities for individuals with speech impairments and disabilities.

The study, titled "Representation of internal speech by single neurons in human supramarginal gyrus," was conducted by Sarah K. Wandelt and colleagues. Their findings have opened up new avenues for further exploration and development in the realm of brain-machine interfaces.