@Wozz,
This may be information you already know, but the brain in the vat scenario was posited by
Hilary Putnam in 1981. If you are curious about looking up more about the actual theory from the lips of the author himself, check out his book
Reason, Truth, and History. Truth be told, the book is not too impressive, but it does have a more extended elaboration on the brain in the vat scenario.
Definitely qualia has a very good point about
Rene Descartes being the locus of the brain in the vat scenario. Specifically, I would look at the first book in his six part
Meditations on First Philosophy addressing universal doubt. On an even deeper level, you can go back farther into Descartes primary methodological treatise entitled
Discourse on the Method, which outlines Descartes style of rationalistic inquiry. In it, he outlines radical skepticism which doubts even the nature of the very things we see (a-posteriori truths) and instead focuses on the things that come before the senses (the a-priori truths). And of course, this is something that
John Locke wholeheartedly refutes first and foremost in
An Essay Concerning Human Understanding, specifically in the refutation of innate ideas. This in turn may give you a very good idea as to the superficial differences in rationalists and empiricists.
You may also want to consider an alternate approach to the vat issue with
Nick Bostrom's simulation argument. In it, instead of the brain in the vat scenario, we are actually put in a position where we could be part of an elaborate computer simulation.
I would honestly start with the basics though (Descartes, Locke, etc) and then get into Putnam because having a substantial foundation in the classical rationalistic/empiricist theories enables you to connect more subtle elements without forming a basis on a third or fourth tier philosopher.