Thu Dec 05 2002 09:10: Sometimes when I'm drifting off to sleep or when I actually am asleep, I experience this weird jerk. Harlan Ellison comes into my room and starts berating me. No, what actually happens is a muscle spasm which, if I'm already asleep, might wake me up with a sudden dream-sensation of violently tripping over something. In an inversion of my overbite belief, I always thought this was just some weird quirk of my biology, but today J. Bradford Delong reveals that it is a general feature of humans. It's your brain unplugging your motion and speech centers so that you don't chase rabbits in your sleep. So when you dream, one part of your brain is acting the Cartesian demon to the other parts, intercepting commands to your body and creating the sensation of their fulfillment.