In the episode that aired last week (ep 14 "Human") lucid dreaming plays a large part in the story. Dr. Rush uses it to communicate with his subconscious in order to solve a very difficult problem. Now, this wasn't a normal go to sleep and dream kind of thing. They figured out how to use the chair with a relative amount of safety. Rush is in the chair throughout the episode. Perhaps a Machine Induced Lucid Dream?

Here is the episode.
http://www.hulu.com/watch/145966/sta...universe-human