I find it is all dependent on the environment and the people I'm with, plus my mood
As a pill popping raver I used to run around a field cuddling strangers telling them how much I loved them... not exactly introvert.
Then again, as the night drew on, you would usually find me at the front, with my head in the bass bin, skinning up a fat one... very isolated and introverted, but thoroughly enjoying the music!
I've also spent the night as part of the crew running the lights for a Dave Angel private party, when I just stayed on the barn mezzanine where the DJ booth was and simply enjoyed watching everyone else having a good time, I even passed up my go on the decks, because I was enjoying doing the lights and watching the crowd dancing so much!
So it totally depends on many factors, be it myself, others around me or the situation / environment.
Edit: shit , thinking about it, that was 24 years ago!...hmmm... I think age plays a big part, been a long time since I stomped in a field cuddling strangers!