Scientists have made remarkable progress in decoding thoughts. A computer connected to electrodes implanted in the brain can interpret not only spoken words or those a person is trying to articulate, but also those simply thought, without the intention of being spoken.
The discovery could revolutionize communication for people with speech disabilities, but raises serious questions about the confidentiality of the human mind.
From Scientific Dream to Reality
For decades, researchers have been trying to give a voice to those who have lost the ability to speak, such as patients with amyotrophic lateral sclerosis (ALS) or victims of a stroke. The idea is simple: if muscles can no longer produce speech, can the brain be "read" directly, and thoughts transformed into words?
In the study published Thursday in the journal Cell, as part of the BrainGate2 project at UC Davis Health, researchers implanted tiny electrodes into the motor cortex of volunteers - the area that sends commands to the speech muscles. Connected to a computer, the system recorded the electrical signals and, with the help of artificial intelligence, learned to recognize nearly 6,000 words with an accuracy of over 97%, synthesizing them with the patient's voice.
The New Challenge: Inner Speech
The novelty of the study is that the system can correctly "guess" words that are only thought. "Imagining a word produced a similar, but weaker pattern," explains the team led by Dr. Erin Kunz from Stanford University. After training, the computer succeeded in decoding entire thought sentences, not just isolated words.
This feature could be extremely useful for patients who tire of speaking, but raises the issue of mental privacy.
In an experiment, the computer detected words corresponding to numbers as participants mentally counted colored shapes. "Measures may be needed to decode only intentional speech," warns Kunz.
"Mental Password" - Shield for Private Thoughts
To protect privacy, researchers tested the system activation only after a "mental password" - the unusual phrase Chitty Chitty Bang Bang. One participant activated the system with an accuracy of 98.75%, ensuring control over when thoughts are decoded.
Christian Herff, a neuroscientist at Maastricht University, told the New York Times that this result "goes beyond the purely technological part and sheds light on the mystery of language."
However, some experts remain skeptical that an implant could capture a large part of spontaneous thoughts, which are rarely well-structured sentences.
Current Perspectives and Limitations
Currently, the accuracy does not allow for fluent real-time conversations, but researchers are optimistic that the technology will evolve. For patients who cannot use their voice, this progress could be revolutionary.
However, the study's authors caution that it is essential for development to be accompanied by strict regulations to protect the confidentiality of thoughts.