UNDATED - Doctors prepare a female patient for a maintenance dose of electroconvulsive therapy, the administering of mild shocks to the brain, in 1995 in Pennsylvania. Shock treatment, as it is sometimes referred to, is more effective now than ever in the treatment of severe depression.The brain, which makes us distinctly human, is unquestionably far more complex than any machine. It weighs about three pounds and is made up of delicate tissue containing billions of cells which regulate the body, learn to navigate the complicated world we live in, and hold a lifetime of memories. Although advances in science and medicine have improved treatment of common brain disorders, the brain still holds many mysteries. (Photo by Joe McNally/Getty Images)
