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Former neuroscientist working on similar stuff here. While the flashy part is the “speech synthesis”, the science breakthrough is actually better frames as an
by maebert 7y ago
Former neuroscientist working on similar stuff here.
While the flashy part is the “speech synthesis”, the science breakthrough is actually better frames as an machine learning problem.
Imagine you record someone moving their hand across a canvas. The hand movement becomes the input, the drawing the output. The ML problem they solved is to reconstruct the output (or at least something that resembles it) from the input. In the study’s case, that’s efferent motor signals.
There is a long history of mapping these kind of signals in the sensorimotor homunculus to the respective muscles they control downstream (and some really cool stuff like prosthetic limbs can already be controlled with it), but speaking is a notoriously hard motor task and requires a lot of muscles to work in unison in very precise ways. When you implant these multi-electrode arrays, you get a few hundred more or less random single neurons, astrocytes, and local field potentials from the nether in between. Nonsense, noisy data. Being able to map this back to the result they produce in the body is technically as complex as astonishing!
- blendo 7y agoThere's a picture of the electrode array on the Nature site, and it looks about 3cm x 3cm, with about 16 x 16 sensors. So 256 inputs to the analysis system. I know nothing about these kinds of electrodes, but how sensitive do they have to be? Sub-microvolt? And how fast? Sub-millisecond? Finally, on the results themselves. If I read it right, the sensors had been previously implanted into epilepsy patients, and were "re-purposed" for this study. So I assume they patients were able to speak? If so, it's trickier to demonstrate advantages for those who have lost the ability to speak.