There are many examples in medicine section: https://en.wikipedia.org/wiki/Self-experimentation_in_medici... which also resulted in fatalities.
If we had a perfect brain-computer-interface, could we grow 3D brain tissue in the lab, hook it up to a computer and do arbitrary processing on it?
An alternative way to view the brain is as a complex switchboard. Instead of doing stuff itself, signals just flow through it and reshape the vessel, like rivers shape the landscape. Of course this is also an incomplete view, but demonstrates at least one alternative metaphor.
Metaphors matter, they are central to how we conduct research.
Also, most of what the brain does isn't creativity, insight, curiosity and all these glorious things, but rather breathing regulation, hormone regulation, control of digestion, muscles, a lot of "body stuff" instead of "abstract, ideal, body-independent stuff". I'd actually argue that everything we think about (even things like morality) have a rooting in our bodily, real existence and nothing is purely abstract.
Not sure what you mean about having a perfect BCI. You could grow 3D brain tissue and do arbitrary processing on it but it wouldn't require a perfect BCI to do that.