In a feat that could eventually unlock the possibility of speech for people with severe medical conditions, scientists have successfully recreated the speech of healthy subjects by tapping directly into their brains. The technology is a long, long way from practical application but the science is real and the promise is there.
Edward Chang, neurosurgeon at UC San Francisco and co-author of the paper published today in Nature, explained the impact of the team’s work in a press release: “For the first time, this study demonstrates that we can generate entire spoken sentences based on an individual’s brain activity. This is an exhilarating proof of principle that with technology that is already within reach, we should be able to build a device that is clinically viable in patients with speech loss.”
To be perfectly clear, this isn’t some magic machine that you sit in and its translates your thoughts into speech. It’s a complex and invasive process that decodes not exactly what the subject is thinking but what they were actually speaking.
Led by speech scientist Gopala Anumanchipalli, the experiment involved subjects who had already had large electrode arrays implanted in their brains for a different medical procedure. The researchers had these lucky people read out several hundred sentences aloud while closely recording the signals detected by the electrodes.
See, it happens that the researchers know a certain pattern of brain activity that comes after you think of and arrange words (in cortical areas like Wernicke’s and Broca’s) and before the final signals are sent from the motor cortex to your tongue and mouth muscles. There’s a sort of intermediate signal between those that Anumanchipalli and his co-author, grad student Josh Chartier, previously characterized, and which they thought may work for the purposes of reconstructing speech.