Waking brain boots up like a computer - LiveScience - MSNBC.com: "As we yawn and open our eyes in the morning, the brain stem sends little puffs of nitric oxide to another part of the brain, the thalamus, which then directs it elsewhere.
Like a computer booting up its operating system before running more complicated programs, the nitric oxide triggers certain functions that set the stage for more complex brain operations, according to a new study. "