Liu Xiaoyun had no idea what was about to happen to him.The helmet he was wearing was wired to a machine; when the machine was turned on, a weird feeling of numbness washed across his scalp. The doctor turned a dial and that feeling was replaced by pain, as if he was being pinched all over, or stabbed by needles. After a few minutes, his body began trembling. It was not until afterward he realized he had been shocked.