Patients who previously showed no fear to external stimuli have shown panic attacks when asked to inhale carbon dioxide. This gives interesting insights into fear mechanisms of the brain.

Why is the sound of nails on a blackboard (and to some of us, even the thought of it) enough to make us wince and cover our ears? How do our ears respond differently to them?

Highly Superior Autobiographical Memory is different from ordinary good memory, and has been linked to a difference in the structure of the brain.