"While we predicted that the emotional centers of the brain would overreact after sleep deprivation, we didn't predict they'd overreact as much as they did," Walker said. "They became more than 60 percent more reactive to negative emotional stimuli. That's a whopping increasethe emotional parts of the brain just seem to run amok."

http://news.yahoo.com/s/livescience/20071022/sc_livescience/emotionsrunamokinsleepdeprivedbrains;_ylt=AsTGJl0q16AWQHAe3PWtkQWs0NUE