Brain scans can show how the brain gets "tired and over-emotional" when someone is deprived of sleep.
US researchers kept volunteers awake for 35 hours and found huge increases in brain activity when shown images designed to make them angry or sad.
http://news.bbc.co.uk/2/hi/health/7056611.stm
http://www.foxnews.com/story/0,2933,304438,00.html
No shit. So does missing out on morning coffee.
