[dmitshur]

There's a short story along these lines I remember reading somewhere, but I could never find it again. It describes the experience of someone whose brain is separated from their body but kept connected to it via a remote connection. Over time there are various experiments or different situations, like going into a cave to experience higher latency, maybe controlling multiple bodies at once, replacing the biological brain with an equivalent simulated one, and some others. I wish I could remember more of the details...

Any chance it's one of the ones you mentioned above, or another someone recognizes? I was able to find that the phrase "brain in a vat" refers to this genre as a whole, but haven't yet found the particular version that I faintly recall reading.