Musical Dreams

I mentioned that I've been reading Musicophilia by Dr. Oliver Sacks, which discusses the strange ways our brains deal with music. I also mentioned that I've been working on The Black Page by Frank Zappa, a particularly difficult piece of music for the drums. I've been extremely focussed on learning this piece - practicing it several times a day and executing the complicated tuplet passages with a metronome and practice pad. I've watched performances of it on video several times and I've been discussing it with other musicians. It's been on my mind so much that I find I've been dreaming it. When I woke this morning I realized that it had been running through my dreams in various forms. At some points I was playing it, at others I was watching it being performed, and at other points it was playing like a soundtrack in the background of totally unrelated activity. In my dreams it was flawless. I'm certain that, even though my muscles haven't learned the whole thing, my brain has recorded it. I've listened to this piece hundreds of times and heard it live at seven different concerts (five FZ tours and two ZPZ tours).

I wonder what Dr. Sacks would say about that. Was it recorded entirely by my brain long ago, only to be released now by this intense scrutiny? Or was it only partially in my memory waiting to have the gaps filled through actual study and practice? Is the brain a complete recorder or does it throw out things it doesn't completely get to make room for more important things? Personaly, I suspect the brain records and stores every experience. The right key could set any of them free, even things we didn't entirely understand.