What do you do when someone exhibits no ability to feel fear? Much like when someone claims they aren't ticklish, the only possible reaction is to try to prove them wrong. Scare 'em, and scare 'em good. For science.

Previously, the amygdala, an almond shaped area of the brain, was thought to be the brain's main region for processing fear. But new research from the University of Iowa shows that it may be more complicated than that.

Scientists incited feelings of panic in three female patients with damaged amygdalae -- women who normally exhibit no signs of fear. This suggests that feelings of intense, overwhelming fear (panic) are located in a different part of the brain than normal fear.