[striking]

The article mentions that

> electrodes implanted in his motor cortex recorded signals of his brain activity

so I'm assuming other thoughts and interactions had little to no effect.

[Ajedi32]

This makes me wonder if "thinking about writing letters" is really an accurate description of what's happening. Was the subject merely thinking about writing letters, or was he actually trying to write them, such that if he weren't paralyzed his muscles would be moving to perform that task?

[striking]

The subject was instructed to actually try and write the letters; the AI they trained on the electrode outputs attempted to return pen stroke velocities.