It's freaky how the brain will just plasticly learn novel motor output interfaces on the fly. It's almost like instead of hard coding a control scheme for anatomy that changes every few million years the strat that brains went for was to be openly reconfigurable to fit around whatever its nerves seem to be hooked up to via observed feedback.
I think they've done tests on this by getting people to pilot novel bodies in VR. But you don't tend to notice it day to day until something weird happens like just now. I was reading a paper book and it had a line of text blacked out as if redacted. Instinctively I go to move my cursor over the black line to see if I can read any text if I highlight it.
Except it's a book and not my computer screen, so the cursor my brain thinks it's moving across my field of vision in front of me doesn't exist. At the same time, my right hand is making a bunch of small involuntary movements next to me. I didn't intend to move it and didn't even notice it was moving until I saw it with my eyes. What I intended to move was my Cursor, something that my brain had learned to understand that it has, and the way it moves this is by actuating the muscles in my right arm, an action that is entirely disconnected from any intent to move my arm, which is a different thing.
I love being a pattern atop this eldritch mess of neurons, it's great