Who learns in a brain-computer interface, the decoder or the brain? · Lobeworks/17

Both.

Who learns in a brain-computer interface, the decoder or the brain?

Both. The decoder learns to map the activity it records onto what the person intends, and the person, watching the result, learns to produce activity the decoder reads well, as monkeys learned to raise the firing of single neurons for a reward in 1969. The human side learns fastest when the new map asks for patterns its neurons already produce. Because both adapt at once, an update to the decoder changes a skill the person built around the old one, which is why a recalibration is closer to a change in treatment than to a software patch.