Not totally sure about the language, so you can correct me if I'm wrong. I've seen them call the prerecorded tracks that are obvious and well known like in Bad "sequences" which I find a little confusing. Then there are the ones you throw down live and loop on an 8 or 16 count or whatever, and is there a special name for those?
When you've got Edge starting a song with an opening riff and then moving into a different tone to solo or add another layer, (like in The Fly or ABOY) my guess has been that it makes better sense for him to live-record the foundational sound on a loop and cue it to repeat rather than starting a prerecorded track halfway through the song. But maybe not. What do you think?