Deep Brain Stimulation

The video we watched in class on deep brain stimulation was really interesting to me. The exact precision the doctors have is amazing to me. It is also really interesting to me that if it was a couple of millimeters lower then the right spot, the person would be uncontrollably crying. It shows how far technology and medicine as come to know you can put electrodes in a persons brain to make them happy. They smile because the pacemaker sends a shock it was really amazing to me. They can cure depression by sending an electronic shock through your brain. The people that had the procedure done felt amazing after wards. The people said they had not felt this way in four years, its amazing what science can do. I would like to know how they found out they could do this and what can go wrong with this procedure.