How scientists discovered the "fear center" of the brain

Fear is one of the most universally understood human emotions. Every one of us is familiar with the feelings, behaviors, and symptoms engendered by fear — so familiar, in fact, that we can sense it in the voices and actions of our friends and loved ones, and even recognize it in the facial expressions of complete… » 10/12/11 9:00am 10/12/11 9:00am

X-rays reveal the disappearing legs of ancient snakes

Snakes are a weird evolutionary mystery, and biologists still aren't sure exactly where they came from. Are they the descendants of land-based lizards that evolved away from legs, or did their ancestors slither out of the sea? X-rays of a recently discovered, 95 million year old fossil may go along way to answering… » 2/08/11 5:00pm 2/08/11 5:00pm