My first guess at these initials, with no context, would be "Public Relations." However, we shouldn't have to guess. In what context did you come across it? Please provide at least a complete sentence and tell us something about the general subject that was under discussion.
Neither one really fits the context, but if I had to guess, I'd say the most probable meaning is "public relations." In the first place, we (in the US) don't usually say "PR" for "public radio" - we say "NPR" for "National Public Radio." In fact, I've never heard PR used to mean "public radio." I wouldn't be surprised to find out that some people use it this way, but I would be surprised to find that it's common. I see, however, that Muse is a British group, so maybe PR=public radio is more common there?
In contrast, it's very common on both sides of the Atlantic to refer to public relations as "PR" - very common indeed. So that's my guess for what it means here - that the song writer is equating public relations to mind control or something like that. But with song lyrics, it's really hard to say.